Comparison of different algorithms for lupus anticoagulant detection: a single-center experience

Background

The laboratory tests for lupus anticoagulant (LA) detection comprise complex and multistep coagulation testing procedures. There is no established gold standard assay or direct comparison of algorithms as recommended by different guidelines.

Objectives

This study aimed to evaluate and compare the LA detection performance of different laboratory algorithms suggested by the existing guidelines.

Methods

The routine LA test data of 1801 plasma samples, including 188 LA-positive and 1613 LA-negative samples, were re-evaluated by applying the algorithms recommended by existing guidelines and were interpreted using various methods. Diagnostic performance indices for each LA detection algorithm were compared with those of the other algorithms. The efficacies of the different interpretation methods were analyzed to determine a suitable interpretation methodology for each assay.

Results

The diagnostic performance for detecting LA varied by the algorithm and method of interpretation used. All laboratory algorithms displayed exceptional diagnostic performance with all diagnostic parameters of >90.0%. Nearly perfect agreement was observed in all algorithms when compared to the Clinical and Laboratory Standards Institute 2014 guideline interpreted by normalized screen-to-confirm ratio (NSCR) and mixing test-specific cutoff (MTC), as a reference assay (Cohen's kappa coefficient, >0.90 [range, 0.94-1.00]). A combination of the index of circulating anticoagulant and NSCR was optimal for interpreting the activated partial thromboplastin time-based test, whereas a combination of the MTC and NSCR was suitable for the diluted Russell's viper venom time-based test.

Conclusion

All laboratory algorithms showed equivalent diagnostic performance. Establishing the best method of interpretation for each assay is recommended to improve LA detection performance.

Evaluation of point-of-care testing device for anemia detection: A cross-sectional method comparison study from Thailand

BACKGROUND

A comparison study is crucial before launching a new medical device; therefore, we compared the Mission Ultra Hb Testing System with the Sysmex XN-3000 automated hematology analyzer in Thai adult males and non-pregnant adult females.

METHODS

Parallel studies were conducted using discarded venous K2-ethylenediaminetetraacetic acid samples from participants requiring hematological investigations. According to the World Health Organization criteria, the participants were categorized as overall, anemia, and non-anemia for analysis.

RESULTS

Three hundred participants were included in this study. In all participants, near-perfect correlation and agreement were observed between the two methods for Hb measurement (r = 0.963, p < 0.001) with an interclass correlation coefficient (ICC) of 0.981 (95% confidence interval [CI]: 0.976-0.985) and Hct measurement (r = 0.941, p < 0.001) with an ICC of 0.965 (95% CI: 0.956-0.972). The sensitivity and specificity of the device in detecting anemia were 86.2% (95% CI: 79.7-91.2) and 98.6% (95% CI: 95.2-99.8), respectively. The area under the curve was 0.976 (95% CI: 0.963-0.989). The device showed average biases of 0.76 g/dl (95% limits of agreement [LOA]: -1.03 to 2.54) for Hb measurement and -2.73% (95% LOA: -9.28 to 3.82) for Hct measurement in all participants.

CONCLUSION

Agreement between the Mission Ultra Hb Testing System and Sysmex XN-3000 was observed. The device was excellent for detecting anemia. However, the essential evidence showing biases of the Hb and Hct measurements obtained from the device was revealed. Laboratory interpretation should be carefully performed, particularly at the near cut-off values.

An MMP/TIMP ratio scoring system as a potential predictive marker of diabetic foot ulcer healing

OBJECTIVES

The mechanism of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in diabetic foot ulcers (DFUs) is unclear. The purpose of this study was to describe changes in MMP-1, MMP-9, and TIMP-1 levels during DFU healing, and to search for any correlation in the changes in MMP levels with wound healing, in order to find possible predictors of healing.

METHODS

Patients with a DFU were recruited and placed into two groups, according to the degree of wound healing: 'good healers' and 'poor healers'. Levels of MMP-1, MMP-9, and TIMP-1 were analysed by ELISA (enzyme-linked immunosorbent assay).

RESULTS

A total of 22 patients participated in the study. The MMP-1 level was significantly higher at weeks zero (W0) and 12 (W12) in 'good healers' than in 'poor healers' (p=0.045 and 0.008, respectively). In contrast, the MMP-9 level was significantly lower in 'good healers' than in 'poor healers' at W0, W4, and W12 (p=0.001, 0.001 and 0.028, respectively). Receiver operator curve (ROC) analysis of the MMP-9 level, MMP-1/TIMP-1 ratio, and MMP-9/TIMP-1 ratio at W0 provided cut-off levels of 0.38, 0.056, and 9.06, respectively, which were best predictive of a reduction in wound area at W4 ('good healers' versus 'poor healers'; thereby predicting wound healing condition at W12) with a sensitivity of 81.8%, 81.8%, and 90.9%, and a specificity of 64.6%, 55%, and 64.6%, respectively.

CONCLUSION

A 'poor healing scoring system' is therefore proposed that could be determined on patient admission, which has the potential to be used clinically as a predictor of healing, thus allowing an appropriate treatment plan to be developed.

Determination of whole transcription profiles and specific pathways in invasive ductal breast carcinoma

Breast cancer is the most common cancer affecting women worldwide including Thailand. Whole transcription profiles of invasive ductal breast carcinoma (IDC) obtained by oligonucleotide microarray should lead to a better understanding of the molecular basis of IDCs, allow for examination of specific markers for diagnosis, and provide novel targets for therapy. This study aimed to detect the whole transcript expression of approximately 35,000 target genes in Thai breast cancer patients, using Affymetrix GeneChip(®) Exon 1.0 Sense Target Arrays. Analysis revealed that the differential expression profiles of 928 genes (423 up-regulated and 505 down-regulated genes) were 2-fold or greater (unpaired t-test, p < 0.05) in invasive ductal breast cancer, compared with normal tissues. The Gene Ontology (GO) databases support important associations in 17 gene sets with p-value < 1E-10 and ≥ 4-fold changes, involving the tumorigenic pathways of cell cycles, extracellular regions, as well as cellular component organization. Likewise, the TGFBR and IL-6 pathways contain gene expression with statistically significant changes in IDC.

Prevalence and hematological parameters of thalassemia in Tha Kradarn subdistrict Chachoengsao Province, Thailand

OBJECTIVE

To determine the prevalence, molecular characteristics and hematological study of thalassemia in Tha Kradarn Subdistrict Chachoengsao Province.

MATERIAL AND METHOD

The present study population consisted of266 participants from Moo 19 Baan Na-Ngam, Chachoengsao Province, Thailand. After blood collection, all samples were screened for thalassemia by initial screening with the OF and DCIP tests and additional testing by CBC, RBC indices, hemoglobin typing and determination of Hb A2 and Hb E. All common alpha-thalassemia mutations were determined using the PCR with allele specific primers and Gap PCR for common deletions.

RESULTS

The prevalence of alpha-thal 1, alpha-thal 2 and beta-thal were found as 2.72%, 11.26% and 0.97%, respectively. Regarding the abnormal hemoglobins, the prevalence of Hb E, Hb Constant Spring and Hb Pakse was 38.45%, 3.69% and 0.78%, respectively. MCV and MCH were significantly different between P-thalassemia as well as a-thal 1 carriers and normal subjects. In all alpha-thal 1 traits, it was found that the MCV and MCH were less than 75 fL and 25 pg, therefore, these parameters can be used for alpha-thal 1 screening.

CONCLUSION

In the present study, the prevalence of thalassemia was similar to previous studies. Moreover, using the combination of OF and DCIP tests compared with MCV, MCH and DCIP tests for the initial thalassemia screening, it was found that the OF and DCIP tests gave more false positive results, which increased the need for further Hb typing. Hence, the MCV and MCH combined with DCIP tests provide cost minimization and practical for a large population-based screening program.

Comparison of clinical pathology examination scores and grade point averages of Royal Thai Army medical cadets

This retrospective study assesses the relationship between clinical pathology (CP) examination scores and grade point averages (GPAs) of Royal Thai Army (RTA) medical cadets. Altogether, 411 of the third-year RTA medical cadets studying CP at Phramongkutklao College of Medicine in 1995-2001 were included in this study. Correlations between CP examination scores, clinical year GPAs, and cumulative GPAs were analyzed by using Pearson's product-moment correlation coefficient. The CP scores showed positive correlations (p < 0.01) with GPAs in the clinical years (4th to 6th) of study (r = 0.616, r = 0.602, and r = 0.540) and cumulative GPAs (r = 0.698). These significant findings may be attributable to the integration of small group teaching and case study discussions, together with traditional lectures and laboratory practice, in the CP course. Our results indicate that CP examination scores can be used as a reliable predictor of success in the 6-year course of study for RTA medical cadets.

HLA-B27 testing in Thai patients using the PCR-SSP technique

We develop the HLA-B27 test kit using the PCR-SSP technique. Five hundred forty blood samples were tested for HLA-B27 by microlymphocytotoxicity test (LCT) and PCR-SSP. It was found that 127 (23.5%) and 134 (24.8%) of these samples were positive for HLA-B27 by LCT and PCR-SSP, respectively. The sensitivity and specificity of the PCR-SSP were 94.8 and 100%, respectively, when using LCT as the standard method. The PCR-SSP positive predictive value was 100%, negative predictive value was 98.3%, and a concordance rate of 98.7%. This study shows that the PCR-SSP is simple, convenient, and a more cost-effective in-house test kit.

Screening for thalassemia and hemoglobinopathy in a rural area of Thailand: a preliminary study

The present study aimed to screen thalassemia and hemoglobinopathy in Baan Na-Ngam, Chachoengsao Province, Thailand. Blood samples were obtained from 266 volunteers; 105 males and 161 females aged 7 to 49 years. Blood samples screened for thalassemia combining the OF and modified DCIP precipitation tests. CBC, RBC indices, hemoglobin typing, HbA2 and Hb E were determined. Combined OF and DCIP tests found that in normal subjects, 128 out of 155 were negative for both, 3 were -/+ pattern, 22 were +/- pattern and 2 was positive for both. Interestingly, one sample showed an abnormal hemoglobin pattern, which could not be determined by automated LPLC. Three beta-thalassemia trait subjects were positive for only the OF test. For the Hb E trait, 57 out of 94 were -/+ pattern; 37 were positive for both tests. Moreover, 14 homozygous Hb E subjects were positive for both tests. The prevalence of beta-thalassemia trait was 1.1%, Hb E trait was 35.3% and homozygous Hb E was 5.3%. Since DNA analysis was not performed, alpha-thalassemia1 and alpha-thalassemia2 traits cannot be excluded. In conclusion, a combination of the OF and DCIP tests is suitable for preliminary screening for thalassemia and hemoglobinopathy. However, RBC parameters, hemoglobin typing and PCR analysis will provide more specific diagnosis, especially in alpha-thalassemias.

Use of the gel test to follow up chimerism in ABO mismatched bone marrow transplantation patient: a case report

OBJECTIVE

The authors report here our experience using the gel test to follow up chimerism in a 5 year old girl with beta thalassemia/Hemoglobin E disease (beta thal/HbE), post allogeneic bone marrow transplantation with Hb E trait HLA identical sibling donor. They were ABO blood group major mismatched donor-recipient pairs (donor and recipient blood group are B and O, respectively).

MATERIAL AND METHOD

Pre and post transplanted EDTA blood samples from the girl with beta thalassemia/ Hemoglobin E were tested for ABO, Rh and direct antiglobulin test (DAT) using the A-B-AB-D-ctl/ AHG card and the titer of anti-A and anti-B were tested by the conventional tube technique. The sex chromosome study and hemoglobin typing were also examined.

RESULTS

In this technique, mixed field agglutination is clearly identified from positive and negative results. The authors detected peripheral recovery, mixed O/B population after transplantation on day +26 with positive DAT. The DAT was negative on day +67 after transplantation and the recipient blood group was completely changed to B on day +123. In addition, Hb typing was changed to Hb E trait with Hb F less than 5 % on day +37. The engraftment of neutrophils, more than 5x10(9)/L, was detected on day+14 and platelet count was more than 20x10(9)/L on day +28. On day +90, the patient was transfusion-independent with the mean Hb level at 11.4 g/dL (10.4-13.1). The sex chromosome and hemoglobin typing were changed to the donor on day +300.

CONCLUSION

The gel test is an alternative method which is simple and helpful in detecting mixed red blood cell populations, particularly in the ABO or other blood group mismatched bone marrow transplantation.

Laboratory approach in Thai patients with venous thrombosis

This retrospective study aimed to analyze laboratory findings in Thai patients with venous thrombosis in Phramongkutklao Hospital from August 1997 to October 2004. Blood samples obtained from 166 patients with ages ranging from 10 months to 87 years were tested for protein S (PS), protein C (PC), antithrombin (AT), factor V Leiden (FVL) and prothrombin G20210A. It was found that low levels of PS, PC, and AT were observed in 23 patients (13.9%), 21 patients (12.7%) and 11 patients (6.6%), respectively. The incidence of combined low levels of anticoagulant factors occurred in 23 patients (13.9%). Three patients (1.8%) were positive for FVL. All patients were negative for prothrombin G20210A. Additionally, 85 patients (51.2%) were negative for all tests. In conclusion, it is recommended that the screening tests for anticoagulant factors PS, PC and AT be used to investigate the causes of thrombosis in Asian populations due to their cost-effectiveness. However, the detection of gene mutations inducing thrombosis should be considered.

Dyslipidemia in Thai rural adults

The present study aimed to determine the prevalence of dyslipidemia in adults in a rural area of Thailand. Random sampling was conducted in 443 volunteers, 187 males and 256 females, aged > or = 35 years in Chachoengsao Province. After a 12-hour fast, the blood was drawn for the analysis of total cholesterol, triglycerides, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol. Mean serum lipids of cholesterol, LDL cholesterol, HDL cholesterol and triglycerides were 207.79 +/- 46.98, 117.26 +/- 36.59, 50.53 +/- 2.14 and 201.21 +/- 131.07 mg/dL, respectively. Nineteen percent of them had cholesterol > or = 240 mg/dL and 10% had LDL cholesterol > or = 160 mg/dL. Seven percent had HDL cholesterol < or = 35 mg/dL. However, LDL/HDL cholesterol ratios > 5, were found in only 0.9%. In conclusion, the prevalence of dyslipidemia was high in rural Thai adults. Further surveillance in this population is essential in verifying the impact of dyslipidemia as a risk of cardiovascular disease in rural Thai adults.

Thalassemia screening among Royal Thai Army medical cadets

Thalassemia, common in Thailand, varies from mild to severe anemia, resulting in work inefficiency, particularly during exertion. Therefore, it is important for military cadets to be screened. The objective of this study was to screen for thalassemia and hemoglobinopathies among Royal Thai Army medical cadets. We tested 358 third-year Royal Thai Army medical cadets for complete blood count, red blood cell indices, hemoglobin (Hb) typing, inclusion bodies, and Hb A2, and Hb E. DNA analysis confirmed alpha-thalassemia, trait detection. The Hb E trait was the most frequent, respectively, in men and women, at 12.61% and 12%, followed by the a-thalassemia1 trait, at 3.3% and 4% and the beta-trait, at 1.5% and 0%. Two cases of homozygous Hb E were found only in men. Interestingly, a mild form of 1-thalassemia/Hb E was found in one male RTA medical cadet. These findings suggest that consistent thalassemia screening should be considered.

Factor V Leiden and prothrombin G20210A mutations in Thai patients awaiting kidney transplant

Renal transplantation provides the best long-term treatment for chronic renal failure, but thrombosis of the transplanted renal artery or renal vein is one of the causes of kidney failure in the early postoperative period. Factor V Leiden (FVL) and prothrombin G20210A mutation are the most frequent genetic abnormalities associated with venous thrombosis. We investigated the prevalence of FVL and prothrombin G20210A by polymerase chain reaction with restriction fragment length polymorphism in 75 Thai patients awaiting renal transplant, and a control group of 106 healthy blood donors. Of those awaiting renal transplant, none was found to carry FVL or prothrombin G20210A mutations. Neither the heterozygous nor the homozygous FVL mutation nor the prothrombin G20210A mutation was detected in the 106 healthy volunteers. Although we failed to detect FVL and prothrombin G20210A mutation among those waiting for a kidney transplant, the population size was small. Further studies need to be performed in order to ascertain if these coagulation mutations are of relevance in predicting patients at risk of early transplant failure.

Iron status of one-year-old infants in a well baby clinic

Seventy-two healthy infants (37 males, 35 females) attending a private well baby clinic were enrolled in the study. Their mean birthweights and body weights at one year of age were 3,079 grams and 10 kilograms, respectively. Blood samples were drawn approximately on their first birthday for evaluating the iron status. Complete blood count, hemoglobin (Hb) typing and DNA analysis for common carrier status of thalassemia and hemoglobinopathis were also determined. According to the infants of serum ferritin, the patients were classified into 4 groups: group 1, iron deficiency anemia (Hb <11 g/dl and ferritin <12 ng/L) in 1 infants (1.4%); group 2, iron deficiency without anemia (Hb >11 g/dl and ferritin <12 ng/L) in 5 infants (6.9%); group 3, borderline iron depletion (ferritin 12-30 ng/L) in 39 infants (54.2%); group 4, iron sufficiency (ferritin >30 ng/L) in 27 infants (37.5%). The iron deficiency state emerged as 8.3 per cent (6/72). There was no significant difference of levels of Hb and mean corpuscular volume (MCV) among the infants with iron deficiency without anemia, borderline iron depletion and iron sufficiency. The results also revealed that 25 out of 72 (34.7%) infants were carriers of thalassemia and hemoglobinopathies. The carrier infants had significant lower Hb and MCV than those of the non-carrier infants with the p-values of 0.004 and 0.000, respectively; while their serum ferritin levels were not significantly different. Additionally, the association of carrier and iron deficiency state was further evaluated. The Hb and MCV among carrier infants with and without iron deficiency were not significantly different. Six infants with carrier state were found to have slightly decreased levels of Hb ranging from 10.3 to 10.9 g/dl with the ferritin ranging from 18.7 to 382.9 ng/L while the remainders had Hb of >11 g/dl. Therefore, 7 out of 72 (9.2%) infants had anemia (Hb <11 g/dl) which was caused by the carrier state of thalassemia and hemoglobinopathies (n=6) and iron deficiency anemia (n=1). The risk factors of iron deficiency status were associated with feeding regimen including continuation of breast feeding until one year of age without adequate haem iron supplement, exclusive formula feeding, inadequacy of solid food supplement with only one meal per day and excluding haem iron from animal liver without substitution. The infants with risk factors had significantly lower levels of serum ferritin (mean 14.1 +/- 1.7 ng/L) than those without risk factors (mean 31.9 +/- 1.9 ng/L) with a p-value of 0.000. In conclusion, adequate haem iron supplement in 3 meals of solid food is essential for the prevention of iron deficiency status in one-year-old infants.

The validity of the Medisafe self-monitoring blood glucose system

Self-monitoring blood glucose (SMBG) meters are widely used in the management of diabetes. The new SMBG meter Medisafe, which is based on the optoelectric colorimetry method, has been introduced. The objective of this study was to validate the Medisafe SMBG meters in comparison with the reference autoanalyzer (Hitachi 717) and to assess the repeatability of the instrument as well as variations of tip replacement. Samples of capillary and venous blood from 299 patients were tested. The correlation coefficients between the Medisafe-measured capillary and venous blood glucose levels and the reference autoanalyzer venous plasma glucose levels were 0.976 and 0.975, respectively. The range of differences from the reference value was examined; only 4% was in excess of +/- 20% of the reference laboratory value, and more than 40% of the values were within 5% of the reference laboratory value. Moreover, repeatability of the Medisafe capillary blood samples measured in three patients with three different blood glucose levels was determined. The coefficients of variation of blood glucose values are within 5%. In addition, the results of mean and SEM from each replication in three patients and glucose measurement from different lots of tips showed no significant difference (p > 0.05). It is concluded that the Medisafe SMBG meter has shown good results in terms of validity and repeatability. Furthermore, it provides safety from blood contamination, which is recommended in countries with a high prevalence of human immunodeficiency virus.

Mutations at the activated protein C cleavage sites Arg336 and Arg562 of factor VIII in Thai patients with venous thrombosis

Venous thrombosis is a multicausal disease, more than one genetic risk factor may cooperate to effect thrombotic risk. Factor V Leiden is found to be an important hereditary risk factor for venous thromboembolism. Analogous to factor V Leiden, a point mutation at amino acid positions Arg336 and Arg562 in factor VIII may predispose patients to thrombosis. Eighty-one Thai patients with venous thrombosis and 100 Thai healthy volunteers have been studied. Neither heterozygous nor homozygous mutations were detected both thrombosis patients or normal volunteers. However, further studies with larger samples of venous thrombosis patients are recommended.

Detection of factor V Leiden in Thai patients with venous thrombosis

The molecular defect underlying activated protein C resistance (APC-R) is caused by a G to A point mutation in the codon for arginine 506 in the factor V gene (factor V Leiden) which is a major risk factor for venous thrombosis, especially in Caucasian populations. This study is an analysis of the Thai population to determine the prevalence of the factor V Leiden mutation. Twenty-seven patients with apparent venous thrombosis were divided into two groups according to APC-R test. Thirteen patients were diagnosed as positive for n-APC-SR, ratio < 0.8 and fourteen patients were diagnosed as negative for n-APC-SR, ratio > 0.8. Two of thirteen APC-R positive patients and one of fourteen APC-R negative patients were found to have the heterozygous allele for the factor V Leiden mutation but the homozygous allele was not detected in these groups of patients. Neither the heterozygous nor homozygous Leiden mutation was detected in 200 healthy volunteer blood donors. In conclusion, our findings indicate that factor V Leiden mutation is related to venous thrombosis in Thai people. Moreover, a further study of other mutations at the activated protein C cleavage sites of factor V and factor VIII is recommended.

Comparison of the RPHA and EIA techniques for the detection of HBs antigen among pregnant Thai women

Five hundred serum samples obtained from pregnant women attending an antenatal clinic in Bangkok were tested for HBsAg by reverse passive hemagglutination assay (RPHA) and enzyme immunoassay (EIA). It was found that 21 (4.2%) and 28 (5.6%) of the sera were positive by RPHA and EIA, respectively. The sensitivity and specificity of the RPHA were 75% and 100%, respectively, when using EIA as the standard method. The RPHA positive predictive value was 100% and the negative predictive value was 98.5%. Accuracy was 98.6%. This study showed that the RPHA was simple and required inexpensive equipment, making it suitable for mass screening. However, the possibility of false negative readings due to low levels of HBsAg should be kept in mind, especially in the blood transfusion practice.

Control cells for both electrical impedance and light scattering automated hematological analyzers: preparation from normal and thalassemic blood samples

The study on quality control of automated blood cell analyzers, Technicon H*1 and Coulter MAXM by using three separately self-prepared control cells was extensively investigated. The three parts of control cells are pseudo-leukocyte and fixed platelets, which are fixed by glutaraldehyde, and control red cells from normal and thalassemic patients preserved and anticoagulated in CPD or CPDA-1. The Technicon H*1 system was based on the principle of light scattering but the Coulter MAXM was based on the principle of electrical impedance for cell counting and measurement. The self-prepared control cells can be satisfactorily utilized as control for each system with statistically significant difference (p < 0.05) for both systems. The expired dates for control cells are different in both systems and should be determined for each system specifically. The control red cells prepared from thalassemic patients were quite satisfactorily useful as an abnormal control for both systems during this study.