HemoCue Hb-801 Provides More Accurate Hemoglobin Assessment in Blood Donors Than OrSense NBM-200

Hemoglobin levels are commonly assessed to prevent causing or worsening of anemia in prospective blood donors. We compared head-to-head the accuracy of different technologies for measuring hemoglobin suitable for use in mobile donation units. We included 144 persons donating platelets at the Central Institute for Blood Transfusion and Immunology in Innsbruck, Austria. Hemoglobin levels were measured in venous blood using the portable hemoglobinometer HemoCue Hb-801 and noninvasively using OrSense NBM-200, and compared to values obtained with the Sysmex XN-430, an automated hematology analyzer employing the sodium lauryl sulphate method, which is broadly used as reference method in everyday clinical practice. Mean age of participants was 34.2 years (SD 13.0); 34.0% were female. Hemoglobin values measured with HemoCue were more strongly correlated with the Sysmex XN-430 (r = 0.90 [95% CI: 0.87-0.93]) than measured with OrSense (r = 0.49 [0.35-0.60]). On average, HemoCue overestimated hemoglobin by 0.40 g/dL (0.31-0.48) and OrSense by 0.75 g/dL (95% CI: 0.54-0.96). When using OrSense, we found evidence for higher overestimation at higher hemoglobin levels (proportional bias) specifically in females but not in males (Pdifference = .003). Sensitivity and specificity for classifying donors according to the hemoglobin donation thresholds were 99.2% (95% CI: 95.3%-100.0%) and 43.8% (23.1%-66.8%) for HemoCue vs 95.3% (89.9%-98.0%) and 12.5% (2.2%-37.3%) for OrSense. Areas under the receiver operating characteristic curves were higher using HemoCue vs OrSense both in females (0.933 vs 0.547; P = .044) and males (0.948 vs 0.628; P < .001). HemoCue Hb-801 measures hemoglobin more accurately than OrSense NBM-200 in the setting of mobile blood donation units. Our findings are particularly relevant for females, having in mind that anemia is more prevalent in females than in males.

Non-invasive hemoglobin measurement devices require refinement to match diagnostic performance with their high level of usability and acceptability

Anemia remains an important global health problem. Inexpensive, accurate, and noninvasive solutions are needed to monitor and evaluate anemia in resource-limited settings. We evaluated the performance of multiple point-of-care hemoglobin devices, including a novel noninvasive smartphone application tested on Apple® and Android® cell phones, Masimo Pronto®, and HemoCue® Hb-301 and Hb-801, against a gold-standard hematology analyzer (reference hemoglobin) using venous blood. We examined correlations between hemoglobin devices and reference hemoglobin, device accuracy (average bias, Bland-Altman plots, clinical performance) and classification bias (sensitivity, specificity) among 299 refugees (10mo-65y) in Atlanta, GA. Semi-structured interviews (n = 19) with participants and staff assessed usability and acceptability. Mean reference hemoglobin was 13.7 g/dL (SD:1.8) with 12.5% anemia. Noninvasive hemoglobin devices were not well correlated with reference hemoglobin (Apple® R² = 0.08, Android® R² = 0.11, Masimo Pronto® R² = 0.29), but stronger correlations were reported with HemoCue® Hb-301 (R² = 0.87) and Hb-801 (R² = 0.88). Bias (SD) varied across each device: Apple®: -1.6 g/dL (2.0), Android®: -0.7 g/dL (2.0), Masimo Pronto®: -0.4 g/dL (1.6), HemoCue® Hb-301: +0.4 g/dL (0.7) and HemoCue® Hb-801: +0.2 g/dL (0.6). Clinically acceptable performance (within ± 1 g/dL of reference hemoglobin) was higher for the invasive devices (HemoCue® Hb-301: 90.3%; HemoCue® Hb-801: 93.4%) compared to noninvasive devices (Apple®: 31.5%; Android®: 34.6%; Masimo Pronto®: 49.5%). Sensitivity and specificity were 63.9% and 48.2% for Apple®, 36.1% and 67.6% for Android®, 45.7% and 85.3% for Masimo Pronto®, 54.3% and 97.6% for HemoCue® Hb-301, and 66.7% and 97.6% for HemoCue® Hb-801. Noninvasive devices were considered easy to use and were the preferred method by participants. Among the only studies to compare multiple point-of-care approaches to hemoglobin testing, the diagnostic ability of HemoCue® was comparable to reference hemoglobin, while noninvasive devices had high user acceptability but considerable biases. Improvements in noninvasive device performance and further testing in anemic populations are recommended before broader use.

Hemoglobin point-of-care testing in rural Gambia: Comparing accuracy of HemoCue and Aptus with an automated hematology analyzer

Background

Anemia is one of the most impactful nutrient deficiencies in the world and disproportionately affects children in low-resource settings. Point-of-care devices (PoCDs) measuring blood hemoglobin (Hb) are widely used in such settings to screen for anemia due to their low cost, speed, and convenience. Here we present the first iteration of Aptus, a new PoCD which measures Hb and hematocrit (HCT).

Aim

To evaluate the accuracy of Aptus and HemoCue® Hb 301 against an automated hematology analyzer (Medonic®) in Gambian children aged 6–35 months and the Aptus’ usage in the field.

Methods

Aptus, HemoCue® and Medonic® were compared using venous blood (n = 180), and Aptus and HemoCue® additionally using capillary blood (n = 506). Agreement was estimated using Bland-Altman analysis and Lin’s concordance. Usage was assessed by error occurrence and user experience.

Results

Mean Hb values in venous blood did not significantly differ between Aptus and HemoCue® (10.44±1.05 vs 10.56±0.93g/dl, p>0.05), but both measured higher Hb concentrations than Medonic® (9.75±0.99g/dl, p<0.0001). Lin’s coefficient between Aptus and Medonic® was r_c = 0.548, between HemoCue® and Medonic® r_c = 0.636. Mean bias between the PoCDs venous measurements was -0.11g/dl with limits of agreement (LoA) -1.63 and 1.40g/dl. The bias was larger for the comparisons between the Medonic® and both Aptus (0.69g/dl, LoA 0.92 and 2.31g/dl) and HemoCue® (0.81g/dl, LoA 0.17 and 1.78g/dl). ROC curves showed an AUC of 0.933 in HemoCue® and 0.799 in Aptus. Capillary Hb was higher with Aptus than HemoCue® (10.33±1.11g/dl vs 10.01±1.07g/dl, p<0.0001). Mean bias was 0.32g/dl with LoA of -1.91 and 2.54g/dl. Aptus‘ usage proved intuitive, yet time-to-results and cuvettes could be improved.

Conclusion

Both PoCDs showed a relatively limited bias but large LoA. Aptus and HemoCue® showed similar accuracy, while both overestimated Hb levels. Aptus showed promise, with its operation unimpaired by field conditions as well as being able to show HCT values.

Replicating measurements of total hemoglobin mass (tHb-mass) within a single day: precision of measurement; feasibility and safety of using oxygen to expedite carbon monoxide clearance

Hemoglobin concentration ([Hb]) is a function of total hemoglobin mass (tHb-mass) and plasma volume. [Hb] may fall by dilution due to plasma volume expansion and changes in the perioperative period may therefore correlate poorly with blood loss. A simple, reliable, repeatable way to measure plasma volume and tHb-mass would have substantial clinical utility. The "optimized carbon monoxide re-breathing method" (oCOR) meets these criteria. However, it is recommended that a minimum of 12 h (when breathing room air) is left between repeat measurements. Twenty-four subjects underwent 3 days of testing. Two oCOR tests were performed (T1 and T2), 3 h apart, with a different CO clearance method employed between tests aiming to keep the carboxyhemoglobin level below 10%. The primary aim was to ascertain whether tHb-mass testing could be safely repeated within 3 h if carboxyhemoglobin levels were actively reduced by breathing supplemental oxygen (PROCA ). Secondary aims were to compare two other clearance methods; moderate exercise (PROCB ), or a combination of the two (PROCC ). Finally, the reliability of the oCOR method was assessed. Mean (SD) tHb-mass was 807.9 ± (189.7 g) (for T1 on day 1). PROCA lowered the carboxyhemoglobin level from the end of T1 (mean 6.64%) to the start of T2 (mean 2.95%) by a mean absolute value of 3.69%. For PROCB and PROCC the mean absolute decreases in carboxyhemoglobin were 4.00% and 4.31%, respectively. The fall in carboxyhemoglobin between T1 and T2 was greatest in PROCC ; this was statistically significantly lower than that of PROCA (P = 0.0039) and PROCB (P = 0.0289). The test-retest reliability for the measurement of total hemoglobin mass was good with a mean typical error (TE) of 2.0%. The oCOR method is safe and can be repeated within 3 h when carbon monoxide is suitably cleared between tests. Using oxygen therapy alone adequately achieves this.

Determination of hemoglobin mass in humans by measurement of CO uptake during inhalation of a CO-air mixture: a proof of concept study

Measuring hemoglobin mass (Hbmass) using the carbon monoxide (CO) bolus rebreathing method is frequently used in research but has yet to be widely used in the clinical practice. The estimation of an adequate CO bolus may be difficult in patients with unknown Hbmass. In the present pilot study, a progressive inhalation technique for CO that leads to a linear individual adjusted COHb increase was evaluated. Sixteen healthy test subjects participated in the study (preliminary investigation: six; main study: ten). The reliability and validity of the new method were evaluated using multiple measurements of Hbmass with and without a defined blood donation and compared to a CO bolus method. The participants inhaled a CO-air mixture (CO concentration: 1500 ppm) for a specific breathing duration. The CO uptake and COHb change were determined simultaneously. The typical error (reliability) in the repeated measurements was 2.4% (CI ± 4.7). The mean difference between the new method and the bolus method was 34 g (±41; P = 0.026). The measured hemoglobin loss in 490 mL of blood was 74 g (±35), and the calculated hemoglobin loss was 77 g (±4) (mean difference 3 g ± 34; P = 0.820). The new method was reliable and valid in a proof of concept study with healthy subjects. The total amount of CO and as a result the COHb increase is individually adjustable. Future studies in clinical settings are needed to determine if the method could be used in disease-specific pathologies associated with changes in Hbmass.

Validation of Masimo Pronto 7 and HemoCue 201 for hemoglobin determination in children from 1 to 5 years of age

OBJECTIVE

To evaluate the accuracy and precision of HemoCue 201 (HemoCue) and Masimo Pronto 7 (Masimo) devices for measuring hemoglobin (Hb) in epidemiological studies, having venous blood samples as a gold standard.

MATERIAL AND METHODS

We measured Hb concentrations in a field sample of 148 children from one to five years of age. Masimo and HemoCue were used for capillary blood samples and an automatic analyzer for venous blood samples. Regression models with no intercept were constructed to measure precision and predictability, concordance correlations to measure accuracy and precision, and Bland-Altman limits of agreement as well as hierarchical linear models to estimate variance.

RESULTS

Both HemoCue and Masimo underestimated Hb concentrations compared to the gold standard. They respectively yielded the following results: regression coefficients of 0.887 and 0.876 with 98.7% and 98.6% predictability; concordance correlation coefficients of 0.183 (p<0.001) and 0.166 (p<0.001); and Bland-Altman variances of -1.51 and -1.62. With regard to Masimo specifically, the three-level Hierarchical Linear Model showed that 57.9% of total variance stemmed from random errors in repeated measures from the same subject.

CONCLUSIONS

HemoCue and Masimo measure lower Hb concentrations than the gold standard. Their accuracy and precision levels are comparable. It is essential to ensure proper use of devices through enhanced training of field workers.

Validation and implementation of a new hemoglobinometer for donor screening at Canadian Blood Services

BACKGROUND

Hemoglobin (Hgb) determination is an essential part of donor qualification. We assessed and implemented a new spectrophotometer for donor Hgb determination.

STUDY DESIGN AND METHODS

Precision, accuracy, and ease of use were assessed on a prototype DiaSpect analyzer (DiaSpect Medical, GmBH, Sailauf, Germany). A protocol to qualify the analyzer was developed and executed preimplementation. Samples were developed for periodic quality control (QC). Postimplementation performance was assessed based on QC results and trending of deferral rates.

RESULTS

Precision was excellent, with a coefficient of variation of 0.53%-1.14% per sample. The correlation coefficient between capillary DiaSpect and venous laboratory autoanalyzer measurements was 0.736. After 169 out of 223 analyzers failed to qualify on our initial protocol, all were successfully qualified with the use of a modified protocol, adjusted to avoid sources of variability. Because commercial controls proved inadequate, in-house samples were developed for periodic QC. Postimplementation, all analyzers had adequate QC results. Deferral rates decreased from 10.1 to 8.1% (p < 0.0001) for female donors and from 0.8 to 0.6% for male donors (p < 0.0001). The system was faster and easier to use compared with our previous two-step process.

CONCLUSION

We successfully implemented a new spectrophotometer, which resulted in greater efficiency, improved ease of use, and decreased deferrals.

Precision of cerebral oxygenation and hemoglobin concentration measurements in neonates measured by near-infrared spectroscopy

BACKGROUND AND AIM

One source of error with near-infrared spectroscopy (NIRS) is the assumption that the measured tissue is optically homogeneous. This is not always the case. Our aim is to assess the impact of tissue homogeneity (TH) on the precision of NIRS measurements in neonates.

METHODS

On 36 term and 27 preterm neonates at least five 1-min measurements are performed on each subject using the OxiplexTS. The sensor position is slightly changed before each measurement while assessing TH. The precision for cerebral tissue oxygenation saturation (StO(2)) and total hemoglobin concentration (tHb) are calculated by repeated measures analysis of variance.

RESULTS

The mean StO(2) is not significantly different between term and preterm infants. The mean tHb is significantly lower in preterm infants (p < 0.01). With increasing TH, the precision of StO(2) increase from 5.6 to 4.6% for preterm and from 11.0 to 2.0% for term infants; the precision of tHb increases from 10.1 to 7.5μM for preterm and from 16.4 to 3.5 μM for term infants. The precision for StO(2) is higher in term than in preterm infants. The precision for tHb shows no significant difference between the two groups.

CONCLUSIONS

The precision of NIRS measurements correlates with tissue homogeneity.

Relationship of quality goals and measurement performance to the selection of quality control procedures for multi-channel haematology analysers

An approach is described for selecting QC procedures based on goals for analytical quality, the performance characteristics of the measurement procedure (imprecision, bias, frequency of errors), and the performance characteristics of the control procedure (probabilities for error detection and false rejection). Performance characteristics of stable sample QC procedures and patient data QC procedures (retained patient specimens, Bull's single-rule algorithm, Bull's multi-rule algorithm) are compared to determine when to apply these different QC procedures to multichannel hematology analysers. Precise, stable methods may be controlled using Bull's single-rule algorithm; less precise, less stable methods require Bull's multi-rule algorithm, retained patient specimens, or stable sample QC procedures; imprecise and unstable methods are best controlled using stable sample QC procedures. "Multi-stage" designs may employ stable samples for "startup" testing, retained patient specimens for short term monitoring, and Bull's single-rule algorithm for long term monitoring.

[Determining the haemoglobin concentration in general practice using the HemoCue method: useful but not completely reliable]

OBJECTIVE

To determine whether the HemoCue haemoglobin value measured in fingertip skin puncture blood corresponds to the reference value measured in venous blood.

DESIGN

Prospective.

METHOD

In two health centres, patients' blood was first drawn from a fingertip skin puncture and the haemoglobin was measured with the HemoCue method (HemoCue B-Haemoglobin AB photometer, Angelholm, Sweden). The same patients were sent to the regional laboratory for laboratory haemoglobin determination. Agreement between the two haemoglobin values was assessed using the method of Bland and Altman.

RESULTS

Both haemoglobin measurements were carried out in 58 patients. The mean HemoCue haemoglobin was 8.0 mmol/l (95% CI: 7.6-8.4) and the mean venous haemoglobin was 8.2 mmol/l (95% CI: 7.9-8.6). Of all values, 2 were above the level of agreement of 2 SD and 17 values were above the level of 1 SD. The sensitivity of the HemoCue measurement was 81% (95% CI: 62-100) and the specificity 95% (95% CI: 88-100). In the population investigated, with a prevalence of anaemia of 28%, the predictive value of a positive HemoCue result was 87% and of a negative result 93%.

CONCLUSION

According to the test characteristics, the HemoCue is a good device for haemoglobin determination. However, in several cases there is a significant difference between the haemoglobin measured with the HemoCue method and the laboratory haemoglobin value. If a reliable haemoglobin value is needed, a laboratory venous haemoglobin assessment is preferred.

Lauryl sulphate haemoglobin: a non-hazardous substitute for HiCN in haemoglobinometry

The haemiglobincyanide (HiCN) method for measuring haemoglobin is used extensively worldwide; its advantage is the ready availability of a stable and internationally accepted reference standard/calibrator. However, its use may create a problem, especially in automated analysers, as the waste disposal of large volumes of reagent containing cyanide may constitute a potential toxic hazard. As an alternative, conversion of haemoglobin to a sulphate derivative by nontoxic sodium lauryl sulphate has been proposed and is available as a commercial product from Toa Medical Electronics Co. Ltd., Japan. This evaluation has shown it to be as reliable and reproducible as HiCN for measuring haemoglobin at all concentrations, by both spectrophotometry and automated analyser. Maximum absorbance is at 534 nm. Total conversion occurs almost instantaneously, and includes methaemoglobin but not sulphaemoglobin. HbF is also measured. The only disadvantage is that solutions of haemoglobin-sulphate are stable for only a few hours at room temperature and up to three weeks at 4 degrees C. Thus, for standardization and calibration of instruments it is necessary to use a sample of blood or lysate the haemoglobin value of which has been assigned initially by the HiCN method.

Different DCCT-aligned HbA1c methods and the GMS contract

BACKGROUND

Previously, different analytical methods could be compared on statistical and clinical grounds. Since 2003, the UK Departments of Health and general practitioners agreed a new primary care contract. This contract utilises clinical targets resulting in a third way to compare analytical methods.

METHODS

We compared two DCCT-aligned HbA1c analysers (Variant II analyser and a Tosoh G7) using 161 randomly selected patient specimens to see if different methods could lead to a difference in the classification for glycaemic control.

RESULTS

Ninety-seven (60.2%) and 109 (67.7%) patient specimens had a HbA1c <or= 7.4% with the Variant II analyser and Tosoh G7 respectively, that is, the two methods differed according to the DM6 GMS target by 12 patients or 7.5% of the total number of patients in the study. When McNemar's test was performed, the difference between the two methods was statistically significant with p<0.00083.

CONCLUSIONS

The National Glycohemoglobin Standardisation Programme has used clinical limits to set standards for HbA1c based on a clinical recommendation from the American Diabetes Association and has resulted in improved generalisability of results. The difference found in this study would not have affected payment under the current GMS contract. However, if the maximum threshold for payment was increased from 50% and/or the HbA1c target was decreased from 7.4%, then payment may be affected. It is important that policy makers and healthcare professionals appreciate the limitations of DCCT alignment for HbA1c methods.

The alkaline haematin detergent (AHD575) method for the determination of haemoglobin in blood--a candidate reference measurement procedure

The article describes the development and evaluation of the alkaline haematin detergent (AHD575) method for the determination of haemoglobin in blood without the need for toxic materials and suitable for use in laboratories in countries with limited resources and restricted import of toxic materials. The validation of the method has been performed in accordance with the requirements set out in the international standard ISO 15193, which describes the procedures necessary for development of a candidate reference measure-ment procedure. The main results were: The trueness of the haemiglobin cyanide (HiCN) method depends upon the diluent used. The international haemiglobin cyanide reference material BCR CRM 522 does not have the same chemical properties as that derived from fresh lysed erythrocytes and cannot be used for calibrating the AHD575 method. The transformation of oxyhaemoglobin to haematin at pH 13 proceeds 5-8 times more rapidly than its conversion to haemiglobin cyanide. The AHD575 method yields results comparable with the HiCN method and uses a readily available crystalline standard of high purity. The introduction of the AHD575 method does not require new reference intervals, the values being directly transferable from (commutable with) the established HiCN procedure.

Evaluation of the utility of the HemoCue 301 haemoglobinometer for blood donor screening

BACKGROUND AND OBJECTIVES

Reliable blood donor screening requires more accurate measure of haemoglobin (Hb) than by either copper sulphate or the haemoglobin colour scale. The HemoCue haemoglobinometer has established a method for this, but it is considerably more expensive; a modified version (HemoCue 301) has now been developed with a cheaper reagent-free cuvette for use in budget-restricted situations. This report describes evaluation of the performance, the assessment of reproducibility and accuracy of this modified analyser against the reference technique for Hb measurement.

MATERIALS AND METHODS

Over 300 routine blood samples from specimens received routinely in a hospital laboratory were tested in accordance with the International Committee for Standardization in Haematology (ICSH) protocol. Accuracy and linearity were confirmed by the reference method with the WHO international haemoglobincyanide reference standard. Tests were also performed on selected samples for checking interference by biochemical abnormalities and leucocytosis. The effects of various sample storage conditions prior to testing were also tested.

RESULTS

Ninety per cent of results were within 4% of true values, 96% within 6% and in only three cases was the deviation > 10%, due to interference by bilirubinaemia and/or C-reactive protein. At an Hb value of 120 g/l for donor selection, there were no cases where the method would have been misleading.

CONCLUSION

HemoCue 301 provides a simple and reliable anaemia screen method, conforming to the requirements of CLIA'88 regulations; it is reliable for discriminating Hb values for donor acceptance. The main advantage is that the cuvettes are significantly cheaper than the previous models, and will not deteriorate in adverse climatic conditions.

International collaborative assessment study of the AHD575 method for the measurement of blood haemoglobin

Accurate, economical methods for haemoglobin determination by laboratories in countries with limited resources are not available. This report provides the results of an international collaborative study evaluating the alkaline haematin detergent (AHD575) method as a reference method for laboratory services with limited resources. The study included 6 laboratories; 3 in East Mediterranean countries, 1 in East Africa and 3 in Europe. The (AHD575) method was evaluated against the HiCN method, with blood samples drawn from healthy and sick subjects. The results indicate that the AHD575 method is suitable for measuring haemoglobin in laboratories at all levels.

Use of the WHO hemoglobin color scale in family welfare clinics in India

A situation is reported for the use of the WHO color scale for the measurement of hemoglobin, which was introduced into India in 1996. Charity family welfare clinics held at a medical college hospital in North India offer free sterilization by tubal ligation under local anesthetic to women following a preliminary screening. An obligatory test of the hemoglobin level is required and must be above 7.0 g/dl for the operation. Some clinics attract large numbers, and the card gives a cheap, rapid and reasonably accurate test, adding to the smooth running and reduction of waiting time. It has proved satisfactory over a 2-year period; 2.3% of participants were shown to have a hemoglobin level of 7 g/dl or less.

Comparison of haemoglobinometry by WHO Haemoglobin Colour Scale and copper sulphate against haemiglobincyanide reference method

Although estimation of haemoglobin is essential for diagnosing anaemia and assessing its severity, many health centres in developing countries do not have the facilities for haemoglobinometry. The WHO Haemoglobin Colour Scale (HCS) method is a simple and inexpensive clinical device that was recently developed in order to diagnose anaemia in such centres. In Indonesia, the copper sulphate specific gravity method is used for blood donor screening and also in primary health clinics in the rural and remote areas. In this study, the HCS method is compared with the copper sulphate method and with an earlier paper scale, the Tallquist method, against the standard haemiglobincyanide spectrophotometric method. The HCS method showed an acceptable level of precision and accuracy for use as a reliable screening tool to diagnose anaemia in patients and also for blood donor screening.

Hemoglobin C and Hemoglobin O-Arab Variants Can Be Diagnosed Using the Bio-Rad Variant IIHigh-Performance Liquid Chromatography SystemWithout Further Confirmatory Tests

Context.—Current standards for laboratory accreditation from the College of American Pathologists state that when high-performance liquid chromatography (HPLC) is used as a screening test, all non-A, non-S abnormal hemoglobin (Hb) variants must be confirmed by an alternative method, including alkaline and acid electrophoresis.

Objective.—To determine whether confirmation of Hb C and Hb O-Arab variants by an alternative method is required when using the Bio-Rad Variant II HPLC system.

Design.—We reviewed 48 478 consecutive hemoglobin identification test results performed on the Bio-Rad Variant II HPLC system during the period November 15, 2000 to January 15, 2003.

Setting.—Special Hematology Laboratory, Department of Pathology, Bellevue Hospital Center, New York, NY.

Main Outcome Measures.—The chromatogram patterns and retention times (RTs) for specimens containing Hb C and Hb O-Arab were analyzed. We compared the results by the HPLC method with those by the confirmatory tests (alkaline and acid electrophoresis) for both variants.

Results.—We identified 3668 cases of abnormal hemoglobin variants, including 660 cases of Hb C trait (17%), 5 cases of Hb O-Arab trait (0.1%), and 1 case of Hb SO-Arab (0.03%). A unique pattern of separation on the chromatogram for Hb O-Arab was revealed, presenting as 2 distinct peaks in 2 different manufacturer-defined RT windows, namely, D and C. The chromatogram for Hb C did not show the D window in any of the reviewed cases. The RT in the C window (C-RT) revealed a statistically significant difference for Hb C and Hb O-Arab (5.18 ± 0.01 minutes and 4.91 ± 0.01 minutes, respectively; P &lt; .001).

Conclusion.—According to our review, the identification of Hb C and Hb O-Arab is accurate using HPLC methodology, as performed by the Bio-Rad Variant II HPLC system. This method can be both confirmatory and diagnostic at the same time.

A grey zone for quantitative diagnostic and screening tests

BACKGROUND

Most quantitative tests do not perfectly discriminate between subjects with and without a given disease and their results do not always allow certainty about disease status for diagnostic or screening purposes. We propose a method to construct a three-zone partition for quantitative tests to avoid the binary constraint of a 'black or white' decision that often does not fit the reality of clinical or screening practice. This partition intentionally includes a grey zone between positive and negative conclusions.

METHODS AND RESULTS

We show that the width of this grey zone depends on the difference between the means of test results for subjects with and without the disease, the variability of the test results and its components (biological, measurement), and the level of the misclassification risks (false positive, false negative) required by the context of use. We illustrate the method by application to the tuberculin skin test and iron deficiency markers in children.

CONCLUSION

This method can be used both to display the discriminatory performance of a quantitative test in a variety of contexts and to scrutinize its components of variability. Due to the simplicity of the graphical representations, the grey zone approach may be useful during the development of quantitative tests and the publication of their performance.

[Standardization of glycosylated hemoglobin in the context of the DAI study]

The results obtained from 85 antidiabetic centers enrolled in the DAI study are presented with regard to the external quality assessment scheme for glycohemoglobin. The materials have been prepared by a laboratory of the network of reference laboratories of the International Federation of Clinical Chemistry (IFCC). To each control a Diabetes Control and Complications Trial (DCCT) traceable target value was assigned. The High-Performance Liquid Chromatography (HPLC) methods for glycohemoglobin are used in 75% of the centers, the immunochemical techniques in 21% and less than 5% is using affinity chromatography based methods. The data collected from the laboratories who completed the set of measurements show that 64% of the centers are well aligned to the DCCT system. The reproducibility of the methods varied between 3.7 and 5.8% (as CV, %) and has to be improved.

Evaluation of the HemoCue compared with the Coulter STKS for measurement of neonatal haemoglobin

OBJECTIVE

To compare the measurement of haemoglobin concentration ([Hb]) using the HemoCue haemoglobinometer with that using the Coulter STKS haemoglobinometer.

DESIGN

Thirty two EDTA samples were taken from neonates. [Hb] was measured in these samples using the HemoCue; the samples were then transferred to the haematology laboratory for [Hb] determination with the Coulter STKS. In addition, [Hb] was determined in 50 different random EDTA neonatal samples already held in the laboratory, using the HemoCue and Coulter STKS.

PATIENTS

Neonates in the intensive care and low dependency Units of the Royal Devon and Exeter Hospital.

INTERVENTIONS

Samples were collected from arterial lines or by venepuncture or heel prick into an EDTA bottle.

MAIN OUTCOME MEASURES

[Hb] using the HemoCue and Coulter STKS methods.

RESULTS

The mean [Hb] measured using the HemoCue was 150.3 g/l (range 78-215) compared with 152.8 g/l (range 78-217) measured using the Coulter STKS, with a mean of the differences of 2.5 g/l. The standard deviation of the differences of the 82 samples was 3.73 g/l. The limits of agreement of the two methods (mean difference +/- 2SD) were -4.8 to +9.8 g/l.

CONCLUSION

With adequate training and monitoring, the HemoCue can be used directly on the neonatal unit for rapid determination of [Hb] to within 7.5 g/l compared with the laboratory Coulter STKS, using much smaller sample volumes.

[Standard material for measurement of hemoglobin A1c]

In Japan, the standardization of measurement of hemoglobin A1c(HbA1c) has been successfully achieved using the standard material(JDS Lot 1, lyophilized, two levels) produced and distributed by the former Shima Committee of the Japan Diabetes Society(JDS). However, methods for measurement of HbA1c other than the HPLC method, for example immunoassay, have been commonly used in the laboratory. Peptide mapping, a candidate method of analytical chemistry for determination of HbA1c, cannot be applied to a lyophilized sample. The present JDS Committee, which continues the work of the Shima Committee, recently certified a deeply-frozen material as the primary standard reference material(five levels) and named it JDS Lot 2. The Lot 2 value of HbA1c is the same as Lot 1, and is different from the National Glycohemoglobin Standardization Program(NGSP) value by -0.3%. It is likely that the standardization of measurement of HbA1c in the future in Japan will be continued using with JDS Lot 2.

The national glycohemoglobin standardization program: a five-year progress report

BACKGROUND

The Diabetes Control and Complications Trial (DCCT) and the United Kingdom Prospective Diabetes Study (UKPDS) demonstrated conclusively that risks for complications in patients with diabetes are directly related to glycemic control, as measured by glycohemoglobin (GHB). In 1994, one year after the DCCT results were reported, the American Diabetes Association (ADA) set specific diabetes treatment goals. However, 1993 College of American Pathologists (CAP) Survey results indicated a lack of comparability of GHB test results among methods and laboratories that represented a major obstacle to meaningful implementation of the ADA guidelines. Thus, an AACC subcommittee was formed in 1993 to develop a standardization program that would enable laboratories to report DCCT-traceable GHB results. This program was implemented in 1996 by the National Glycohemoglobin Standardization Program (NGSP) Steering Committee.

APPROACH

We review the NGSP process and summarize progress in standardization through analysis of CAP data.

CONTENT

Since 1996, the number of methods and laboratories certified by the NGSP as traceable to the DCCT has steadily increased. CAP GH2-B survey results reported in December 2000 show marked improvement over 1993 data in the comparability of GHB results. In 2000, 90% of surveyed laboratories reported GHB results as hemoglobin A(1c) (HbA(1c)) or equivalent, compared with 50% in 1993. Of laboratories reporting HbA(1c) in 2000, 78% used a NGSP-certified method. For most certified methods in 2000, between-laboratory CVs were <5%. For all certified methods in 2000, the mean percent HbA(1c) was within 0.8% HbA(1c) of the NGSP target at all HbA(1c) concentrations.

Variability in hemoglobin levels: clinical implications. Case study of the anemic patient

A historical, prospective, multicenter, observational study was conducted on data from October 1996 to December 1997 to determine the impact of hemoglobin (Hb) variability on the interpretation of maintenance anemia management outcomes in hemodialysis patients. Trends in mean Hb levels were retrospectively analyzed to determine whether there were any differences between 1-month Hb averages versus 3- or 6-month rolling averages. Results showed that: (a) Hb measurements exhibit wide variability between patients and within patients, regardless of the assessment method used, and (b) it is difficult to maintain patients within the 1 g/dL Hb spread recommended by NKF-K/DOQI. The largest variations in Hb readings were observed in 1-month readings, while 6-month rolling averages exhibited the least variability. These data illustrate the importance of assessing long-term trends in laboratory data before making incremental or decremental modifications in the anemia prescription.

Bedside Hemoglobinometry in Hemodialysis Patients: Lessons from Point-of-Care Testing

The HemoCue B-hemoglobin test system (HemoCue, Inc., Mission Viejo, CA) is a photometric method for rapid bedside determination of hemoglobin (Hb). We compared the performance of HemoCue measured Hb against Coulter STK-S (CSTK) measured Hb in chronic hemodialysis (HD) patients in two different settings. In the first setting, Hemocue analysis was performed by multiple HD technicians (n = 132). In the second setting, a nurse trained in proper specimen handling performed the HemoCue analysis (n = 74). Simultaneous measurement of Hb by the CSTK method was performed. First setting: Hb was 11.1+/-1.66 (SD) g/dl by CSTK and 11.7+/-2.29 g/dl by HemoCue. The HemoCue method consistently overestimated Hb by an average (SD) of 0.63 (1.267) g/dl (95% CI = 0.42 to 0.85). Hb was overestimated in 25.7% and underestimated in 2.3% of the patients by 1 g/dl or more. Thus, the HemoCue system was accurate within 1 g/dl only 72% of the time. Second setting: HemoCue overestimated Hb by an average (SD) of 0.29 (0.52) g/dl (95% CI, 0.17 to 0.41). Only 4% of all patients had errors in estimation of 1 g/dl or more. Thus, HemoCue was accurate in 96% of the patients within 1 g/dl. After reviewing the two protocols, the primary difference in the two studies was the technique used to obtain the specimens. When performed properly, Hb testing using the HemoCue testing system had a high level of agreement with CSTK. Appropriate training in specimen handling, as well as test performance, will increase accuracy and reliability of bedside hemoglobinometry.

Field evaluation of who hemoglobin color scale in West Java

The results obtained with a WHO hemoglobin (Hb) colour scale were evaluated in a field study in Chibubur district in Java island by comparison with hemoglobin values obtained by an automated blood cell analyzer K-800 (Sysmex. Kobe, Japan). When the color scale test was performed following the instructions for use. Hb values observed were usually higher than the values obtained by the analyzer. Thirty microl blood was loaded on the filter paper and an 60 sec waiting period was used. The sensitivity of results obtained with the color scale was 23.3% (14/60), and specificity was 96.6% (58/60). We propose an additional testing method based on our results.

Evaluation of the HB-Quick: a portable hemoglobinometer

OBJECTIVE

The Hb-Quick is a new portable hemoglobinometer that uses disposable cuvettes to measure the total hemoglobin concentration of capillary, venous, or arterial blood. Therefore, the objectives of this study were 1) to evaluate the performance of this compact, battery-powered hemoglobinometer by assessing its precision, accuracy, and linearity, 2) to determine whether its measurements suffer from interference by hemolysis, bilirubin, fetal hemoglobin, or hemodilution, and 3) to establish whether it can easily be used by clinical personnel with little or no laboratory training.

METHODS

The precision of the test instrument was assessed by making repeated measurements on blood samples. Its accuracy and linearity were evaluated by comparing its measurements with the internationally accepted cyanmethemoglobin method. Samples of whole blood with and without bilirubin, fetal hemoglobin, hemolysis, and hemodilution were also analyzed to determine if any interference occurred when these disturbances were present, and it was placed in physicians' offices to evaluate its use by non-laboratory personnel.

RESULTS

Repeated measurements on blood samples with a wide range of hemoglobin concentrations were consistent with the precision specification (0.25 g/dl). The bias of the new hemoglobinometer was calculated as the mean difference between its readings and measurements with the cyanmethemoglobin method, and its accuracy as the standard deviation of the differences between the two methods. As assessed in this manner, the new hemoglobinometer had a bias of -0.04 g/dl and an accuracy of 0.40 g/dl. The linearity was checked over a hemoglobin concentration range from 0 to nearly 30 g/dl. There was a highly significant linear relationship between its readings and measurements with the cyanmethemoglobin method (slope = 0.997, y-intercept = 0.005, r = 0.999). Complete hemolysis of the sample increased the readings on average by only 0.22 g/dl. Bilirubin (17.5 mg/dl) increased the reading by an average of 0.29 g/dl, and fetal hemoglobin (76.5% HbF) reduced the readings by an average of only 0.035 g/dl. Diluting blood samples with saline also did not appreciably affect its accuracy.

CONCLUSIONS

The new hemoglobinometer is fast and easy to operate. No sample preparation or pipetting is required. To operate the instrument, the user simply allows a drop of blood to fill the disposable cuvette by capillary action and inserts the cuvette into the instrument. The instrument analyzes the 10 microl sample and displays the results in less than 10 seconds. The interference caused by hemolysis, hemodilution with saline, fetal hemoglobin, and bilirubin were too small to be of any dinical importance. Tests in physician's offices indicated that clinical personnel with little or no formal laboratory training could successfully use this device. The observed precision, accuracy, linearity, and freedom from interference indicate that this hemoglobinometer is suitable for near-patient testing in a wide range of clinical settings including physicians' offices.

Hemoglobin and hematocrit: an analysis of clinical accuracy. Case study of the anemic patient

Hemoglobin (Hgb) and hematocrit (Hct) are often used interchangeably to evaluate anemia in dialysis patients. Hgb is the preferred method in most European countries, while Hct is generally used by clinicians in the United States. This article examines the comparative accuracy of these two values, including a same-patient assessment of laboratory samples. These data illustrate that Hgb is a more accurate method of assessing anemia. Using Hgb may help nurses and patients by: (a) decreasing variability in laboratory assessment, (b) avoiding ongoing errors in anemia measurement, (c) decreasing the nursing time spent on anemia management, and (d) increasing the potential for patients remaining in the recommended DOQI target Hgb range of 11 g/dL to 12 g/dL.

[How to achieve analytical reliability of hemoglobinometry]

Three kits of reagents manufactured by RENAM Research and Production Unit provide the analytical reliability of hemoglobinometry. The kits contain: 1) dry powder transforming agent; 2) four calibration standard solutions of hemoglobin cyanate requiring no dilution; 3) three highly purified stable solutions of hemoglobin (simulating human blood) with attested concentrations of hemoglobin from 50 to 200 g/liter.

Accuracy of a portable haemoglobinometer in clinical practice

The haemoglobin (Hb) levels of 100 blood samples submitted to the haematology laboratory of Groote Schuur Hospital were estimated by 3 clinical observers using the Buffalo Medical Specialties (BMS) portable haemoglobinometer. The average error was between 5% and 6% of the laboratory Hb value (0.6 g/dl). It is concluded that the BMS machine, besides being easy to use and giving a rapid result, is also sufficiently accurate for clinical practice.

An assessment of the operating characteristics of Coulter Counter Model S-Plus STKR

BACKGROUND AND METHODS

The operating performance of the Coulter Counter S Plus STKR was evaluated in two hospital laboratories in Rome and in Florence. Experimental design conformed to both the ICSH and NCCLS Standards for the evaluation of hematologic analyzers, and to the ECCLS guidelines for the multicenter evaluation of analyzers in clinical chemistry.

RESULTS AND CONCLUSIONS

Cell counts in K3 EDTA were unchanged over 6 hours at room temperature and 72 hours at 4 degrees C, while MCV, MPV and leukocyte differentials were far less stable. Carry over, precision and linearity met the manufacturer's specifications, while a satisfactory relative accuracy was demonstrated by determining reference values on an adult reference group and by comparing the instrument with the previous model S Plus IV D. The accuracy of the leukocyte differentials was evaluated by the microscope reference method, and our results seemed to validate the hypotheses that the STKR model counts: i) eosinophils, basophils and banded neutrophils among GR; ii) variant lymphocytes among LY, and iii) various abnormal cells among mononuclear cells. However, in spite of this statistical significance, some difficulties in correctly classifying the mononuclear population were demonstrated.

The distribution of selected hematology measurements in the CAP survey

Investigation of the 1978 CAP Hematology Survey results for hemoglobin, hematocrit, erythrocyte count, leukocyte count, prothrombin time, and partial thromboplastin time with respect to the assumption of normality and the method for detecting outliers was performed. The findings indicate that the assumption of normality, while not exactly valid, is reasonable for the purposes of the Survey, but that the method of determining outliers may be too stringent in the case of hemoglobin, hematocrit, erythrocyte count, and leukocyte count, and not appropriate for prothrombin time and partial thromboplastin time. These findings are similar to those reported earlier for selected chemistry and immunology constituents in the CAP Survey.

The status of methods of calibration in hematology

Three years ago, the authors described methods for calibration and quality control of Coulter automated hematology instruments. These and other methods have received fairly widespread use in hematology laboratories. The effectiveness of such use was tested through special questionnaires conducted by the College of American Pathologists in 1978. Current information indicates no clear-cut advantages between fresh whole blood and preserved-cell control materials when properly used for calibration or quality control procedures. Minor but troublesome differences persistently appear between manual or semiautomated methods and in results on fully automated systems. Likewise, daily internal quality control may be monitored by preserved cells or by continuous process control using patient samples. The various systems for calibration and quality control have certain advantages and disadvantages.

Comparison of the Sahli and grey wedge haemoglobinometers

Experiment confirms that the MRC grey wedge photometer is better for haemoglobinometry than the Sahli haemoglobinometer. However, there is considerable observer variation and the precision of those who undertake haemoglobinometry should be studied by analysis of duplicates. Only in this way can the significance of any measurements obtained be assessed.

[How effective are simple laboratory tests (Hb, BSG) in the early diagnosis of stomach neoplasms]

Up to now only early resection has proven of value in healing gastric carcinoma. It is therefore mandatory that the pathologic lesion be diagnosed as early as possible. Thus, patients with persistent epigastric complaints under symptomatic treatment should undergo endoscopy even if blood parameters are still within normal limits. The fact that, among all our gastric cancers diagnosed in 1977 by endoscopy, 23% were classified as early cancers indicates that the method is well suited to establishing true early diagnosis.