Absolute neutrophil counts from automated hematology instruments are accurate and precise even at very low levels

A critical analysis of CellaVision systems in the modern hematology laboratory

OBJECTIVE

This review aims to provide a comprehensive analysis of the current literature regarding the use of CellaVision digital morphology systems and to assess the emerging applications, their potential to supplement current diagnostic pathways, and-importantly-appreciate their practical and perceived limitations.

METHODS

A manual literature review was conducted to identify relevant journal articles and published abstracts as they relate to the application of CellaVision systems to hematology laboratory practice in human patients.

RESULTS

CellaVision systems can characterize cellular morphology with overall a high degree of accuracy-in particular, for neutrophils; lymphocytes; and common red blood cell changes, including target cells. Challenges remain, however, with the detection of particular important findings, including immature granulocytes and red blood cell agglutination. The application of CellaVision systems to emerging areas such as telepathology and parasitology are evolving, with an increasing volume of literature highlighting the technology's utility.

CONCLUSION

CellaVision systems and associated digital technologies are poised to play an increasingly important role in hematology laboratories, with promises of enhanced accuracy and improved workflows. Several critical deficiencies highlight the necessity for continued research to support their transition into routine clinical practice.

Performance evaluation of Rayto RT-7600Vet hematology analyzer in side-by-side comparison with manual hematological methods for apparently healthy Cholistani cattle blood

The present study is the first from Pakistan being reported with an objective to assess performance of Rayto RT-7600Vet hematology analyzer (HA) for Cholistani cattle blood (n = 134), in comparison to the manual hematological methods. The four hematological attributes viz. total erythrocyte count (TEC), hemoglobin (Hb), packed cell volume (PCV) and platelet count (PLT) were deduced through HA (A) and manual (M) methods. Various statistical tests were implied to ascertain level of interrelationship, accuracy and level of agreement between the two methods. All attributes attained through manual methods had high positive, leptokurtic distribution (having many outliers) except for PLT-M and PCV-M. The coefficient of variation for attributes attained through HA and manual methods ranged from 16-24% and from 16-59%, respectively. Comparison between the overall results revealed that all the studied attributes, except TEC, were significantly (P≤0.05) different for both methods. A weak relationship was noticed between the attributes attained through two methods as indicated by weak r-values and adjusted r-square values. The reliability level of estimating Hb and PCV had highest intraclass correlation coefficient value of 0.722 and 0.555 for average measures, respectively. However, accuracy level, as determined through Lin's concordance correlation coefficient was highest for TEC (0.9504) for both analytical methods. Poor level of agreement, in general, was shown for the two methods of analysis regarding all four hematological attributes through Bland and Altman test. In conclusion, the Rayto RT-7600Vet) may present data having higher skewness, kurtosis, and CV%, however, they are valid for multi-species hematological analysis. Caution must however, be taken in interpreting their results with corrected reference intervals and CV% for each machine and for each tested attribute.

Digital Imaging and AI Pre-classification in Hematology

A leukocyte differential of peripheral blood can be performed using digital imaging coupled with cellular pre-classification by artificial neural networks. Platelet and erythrocyte morphology can be assessed and counts estimated. Systems from a single vendor have been used in clinical practice for several years, with other vendors' systems, in a development. These systems perform comparably to traditional manual optical microscopy, however, it is important to note that they are designed and intended to be operated by a trained morphologist. These systems have several benefits including increased standardization, efficiency, and remote-review capability.

Diagnostic performance of the CellaVision preclassification neutrophil count - time to bypass the reclassification?

OBJECTIVES

The objective of this study was to perform a method comparison between the CellaVision preclassification neutrophil count and the reclassification neutrophil count performed by trained laboratory technicians, and to evaluate the diagnostic performance of the preclassification neutrophil count at clinical decision levels.

METHODS

We retrospectively identified patient samples through 2019-2022 in which the differential count was performed on Cellavision (n = 4,354). Data on sample characteristics and leukocyte- and differential counts was extracted from the electronic medical journal. For each sample, data containing the pre- and reclassification leukocyte classification, respectively, was extracted from the Cellavision software. Method comparison between the pre-and reclassification neutrophil count was performed using Bland Altman analysis. Diagnostic performance of the preclassification neutrophil count was evaluated according to four pre-specified categories of results with the reclassification as reference method.

RESULTS

The median difference between the pre- and reclassification neutrophil count was 0.044 x 109/L. The preclassification neutrophil count categorised 95.6% of all samples correctly according to the four categories. The sensitivity, specificity, positive predictive value and negative predictive value for detecting neutrophilia > 7.00 x 109/L was 98.8%, 97.2%, 95.8%, and 99.2%, respectively. In samples with leukopenia (n = 543), the sensitivity, specificity, positive predictive value and negative predictive value for detecting severe neutropenia (< 0.50 x 109/L) was 97.7%, 99.1%, 98.6%, and 98.5%, respectively.

CONCLUSION

The diagnostic performance of the CellaVision preclassification neutrophil count was satisfactory. The preclassification neutrophil count may be released to the electronic medical journal to improve turnaround time and benefit laboratory management.

Genetic background of hematological parameters in Holstein cattle based on genome-wide association and RNA sequencing analyses

Hematological parameters refer to the assessment of changes in the number and distribution of blood cells, including leukocytes (LES), erythrocytes (ERS), and platelets (PLS), which are essential for the early diagnosis of hematological system disorders and other systemic diseases in livestock. In this context, the primary objectives of this study were to investigate the genomic background of 19 hematological parameters in Holstein cattle, focusing on LES, ERS, and PLS blood components. Genetic and phenotypic (co)variances of hematological parameters were calculated based on the average information restricted maximum likelihood method and 1,610 genotyped individuals and 5,499 hematological parameter records from 4,543 cows. Furthermore, we assessed the genetic relationship between these hematological parameters and other economically important traits in dairy cattle breeding programs. We also carried out genome-wide association studies and candidate gene analyses. Blood samples from 21 primiparous cows were used to identify candidate genes further through RNA sequencing (RNA-seq) analyses. Hematological parameters generally exhibited low-to-moderate heritabilities ranging from 0.01 to 0.29, with genetic correlations between them ranging from -0.88 ± 0.09 (between mononuclear cell ratio and lymphocyte cell ratio) to 0.99 ± 0.01 (between white blood cell count and granulocyte cell count). Furthermore, low-to-moderate approximate genetic correlations between hematological parameters with one longevity, 4 fertility, and 5 health traits were observed. One hundred ninety-nine significant SNP located primarily on the Bos taurus autosomes (BTA) BTA4, BTA6, and BTA8 were associated with 16 hematological parameters. Based on the RNA-seq analyses, 6,687 genes were significantly downregulated and 4,119 genes were upregulated when comparing 2 groups of cows with high and low phenotypic values. By integrating genome-wide association studies (GWAS), RNA-seq, and previously published results, the main candidate genes associated with hematological parameters in Holstein cattle were ACRBP, ADAMTS3, CANT1, CCM2L, CNN3, CPLANE1, GPAT3, GRIP2, PLAGL2, RTL6, SOX4, WDFY3, and ZNF614. Hematological parameters are heritable and moderately to highly genetically correlated among themselves. The large number of candidate genes identified based on GWAS and RNA-seq indicate the polygenic nature and complex genetic determinism of hematological parameters in Holstein cattle.

Rapid Absolute Neutrophil Count Testing Guides Targeted Antimicrobial Therapy in Febrile Pediatric Oncology Patients

OBJECTIVES

It is well established that early antibiotic administration leads to improved outcomes in febrile neutropenic patients. To achieve this, many institutions administer empiric antibiotics to all febrile oncology patients in the emergency setting, before knowing their neutropenic status. This study evaluates the role of rapid absolute neutrophil count (ANC) testing in the targeted antimicrobial management of nonneutropenic febrile oncology patients.

METHODS

We conducted a retrospective review of patients 19 years or younger presenting to the pediatric emergency service with an oncologic process and fever or history of fever. We examined the administration of antibiotics and outcomes in nonneutropenic patients.

RESULTS

We included 101 patient encounters, representing 62 distinct patients. The rapid ANC test influenced antibiotic management in 94% (95/101) of patient encounters and resulted in no antibiotics or targeted antibiotic therapy in 88% (60/68) of nonneutropenic patients. Use of the rapid ANC test to guide treatment would have spared antibiotic administration in 68% (46/68) of well-appearing nonneutropenic patients with no alternate indication. No well-appearing, nonneutropenic patient had a positive blood culture, and only 1 required hospital admission on a repeat visit.

CONCLUSIONS

The rapid ANC is a useful tool to balance the goal of early antibiotic administration in febrile neutropenic oncology patients while promoting antibiotic stewardship in this vulnerable population.

Association of an emergency department febrile neutropenia intervention protocol with time to initial antibiotic treatment

BACKGROUND

Earlier initial antibiotic treatment for febrile neutropenia is associated with improved clinical outcomes. This study was conducted to evaluate the association of an emergency department (ED) intervention protocol with time to initial antibiotic treatment for febrile neutropenia patients.

METHODS

We conducted a cohort study of adult ED febrile neutropenia patients before and after implementation of an intervention protocol. Analyses included comparison of means and medians, Kaplan-Meier estimates, multivariable regression analyses, interrupted time-series analyses, and causal mediation analyses. The intervention protocol included specific triage and process-of-care actions to reduce the primary outcome of time to initial antibiotic treatment.

RESULTS

There were 69 patients in the 12-month preintervention period and 52 patients in the 8-month postintervention period. The mean (±SD) times to initial antibiotics were 197.6 (±85.4) min for the preintervention group and 97.7 (±51.0) min for the postintervention group (difference of 99.9 min with 95% confidence interval [CI] = 73.5 to 126.4, p < 0.001). The patients' probability for receiving initial antibiotics within 90 min was severalfold greater (adjusted risk ratio = 10.31, 95% CI = 4.99 to 21.30, p < 0.001) for the postintervention group versus preintervention group. ED length of stay, hospital length of stay, 30-day readmissions, and 30-day all-cause mortality were not different between the study groups. The association of the intervention protocol with time to initial antibiotics appeared to be mediated through times to treatment room placement, report of absolute neutrophil count, and initial antibiotic order.

CONCLUSIONS

The intervention protocol was associated with a significant reduction in time to initial antibiotics for ED patients with febrile neutropenia. This association appears to be facilitated through specific intermediate process-of-care variables. A larger multicenter study is needed to assess the potential effects of an ED febrile neutropenia protocol on patient-centered clinical outcomes and resource utilization.

Prediction of leukocyte counts during paediatric acute lymphoblastic leukaemia maintenance therapy

Maintenance chemotherapy with oral 6-mercaptopurine and methotrexate remains a cornerstone of modern therapy for acute lymphoblastic leukaemia. The dosage and intensity of therapy are based on surrogate markers such as peripheral blood leukocyte and neutrophil counts. Dosage based leukocyte count predictions could provide support for dosage decisions clinicians face trying to find and maintain an appropriate dosage for the individual patient. We present two Bayesian nonlinear state space models for predicting patient leukocyte counts during the maintenance therapy. The models simplify some aspects of previously proposed models but allow for some extra flexibility. Our second model is an extension which accounts for extra variation in the leukocyte count due to a treatment adversity, infections, using C-reactive protein as a surrogate. The predictive performances of our models are compared against a model from the literature using time series cross-validation with patient data. In our experiments, our simplified models appear more robust and deliver competitive results with the model from the literature.

Improving Time to Antibiotics for Pediatric Oncology Patients With Suspected Infections: An Emergency Department-Based Quality Improvement Intervention

OBJECTIVE

Studies in pediatric patients with fever and neutropenia demonstrate that shorter time to antibiotics is associated with a decrease in pediatric intensive care unit admissions and in-hospital mortality. In 2012, a 2-phase quality improvement intervention was implemented in a pediatric emergency department (ED) to improve care for this high-risk patient population.The objective was to determine if the introduction of (1) a rapid absolute neutrophil count (ANC) test and (2) a standardized prearrival process decreased time to antibiotics for febrile hematology/oncology(heme/onc) patients presenting to the ED.

METHODS

The rapid ANC test introduced in February 2012 decreased turn-around-times in the laboratory from 60 to 10 minutes. The standardization of the prearrival communication between the heme/onc team and ED was implemented in August 2012 as part of a clinical standard work pathway for heme/onc patients who presented to the ED with fever and possible neutropenia. Time from arrival to the ED to administration of first antibiotic was measured.Data from January 2011 to December 2013 were analyzed using statistical process control.

RESULTS

Seven hundred eighteen encounters for 327 patients were included. After the rapid ANC test, the proportion of patients who received antibiotics within 60 minutes of arrival increased from 47% to 60%. There was further improvement to 69% with implementation of the clinical standard work pathway. Mean time to antibiotics decreased from 83 to 65 minutes (21% decrease).

CONCLUSION

This 2-phase quality improvement intervention increased the proportion of patients who received antibiotics within 60 minutes of arrival to the ED. Similar processes may be implemented in other pediatric EDs to improve timeliness of antibiotic administration.

Considerations for point-of-care diagnostics: evaluation of acridine orange staining and postprocessing methods for a three-part leukocyte differential test

There exists a broad range of techniques that can be used to classify and count white blood cells in a point-of-care (POC) three-part leukocyte differential test. Improvements in lenses, light sources, and cameras for image-based POC systems have renewed interest in acridine orange (AO) as a contrast agent, whereby subpopulations of leukocytes can be differentiated by colorimetric analysis of AO fluorescence emission. We evaluated the effect on test accuracy using different AO staining and postprocessing methods in the context of an image-based POC colorimetric cell classification scheme. Thirty blood specimens were measured for percent cell counts using our POC system and a conventional hematology analyzer for comparison. Controlling the AO concentration used during whole-blood staining, the incubation time with AO, and the colorimetric ratios among the three population of leukocytes yielded a percent deviation of 0.706%, ? 1.534 % , and ? 0.645 % for the lymphocytes, monocytes, and granulocytes, respectively. Overall, we demonstrated that a redshift in AO fluorescence was observed at elevated AO concentrations, which lead to reproducible inaccuracy of cell counts. This study demonstrates there is a need for a strict control of the AO staining and postprocessing methods to improve test accuracy in these POC systems.

Impact of Integrating Rumke Statistics to Assist with Choosing Between Automated Hematology Analyzer Differentials vs Manual Differentials

BACKGROUND

To optimize precision of nucleated blood cell counting, the clinical laboratory scientist should post the automated differential rather than the manual differential if the former is within the 95% CI of the latter, as determined by the "Rumke statistic." The objective of this study was to determine the potential impact of real-time, computer-assisted use of Rumke statistics for more judicious use of the automated vs digitally imaged, manual differential.

METHODS

Complete blood counts with automated differentials produced by a XE5000™ hematology analyzer (Sysmex) were compared with both the DM96 (CellaVision™ AB) preclassification differentials and the posted reclassified manual differentials, using the Rumke 95% CIs as calculated using the Clopper-Pearson method.

RESULTS

A total of 44.7% of manual differentials had no statistical or clinical justification over the automated differential. In addition, 31.1% of manual differentials had statistical discrepancies between the instrument absolute neutrophil count (IANC) and manual absolute neutrophil count (ANC). Nineteen of these IANC/manual ANC discrepant samples had ANCs below 1500/μL, a decision level for cancer treatment. Holding the IANC when it is less than 2000/μL until after manual smear review would have prevented the posting of any IANC vs manual ANC discrepant results at the 1500/μL ANC decision threshold.

CONCLUSIONS

A real-time operator alert concerning the statistical identity of imaging device differentials vs automated differentials could have reduced manual differentials by nearly 45%. Not posting unnecessary manual differentials for the cases with IANC/manual ANC discrepancies would have likely reduced clinical error/confusion.

Accuracy of the CellaVision DM96 platform for reticulocyte counting

CONTEXT

Many hematology laboratories have adopted semi-automated digital platforms for routine use and the evidence supporting their use is increasing.

AIMS

The CellaVision platforms are among the most thoroughly studied digital hematology platforms; we wished to determine the accuracy of CellaVision for reticulocyte counting.

DESIGN MATERIALS AND METHODS

We compared reticulocyte counts performed manually, using the Beckman Coulter LH750 automated analyzer and with the CellaVision DM96 platform. We analyzed the results for pair-wise correlation and bias, and precision.

STATISTICAL ANALYSES USED

Analyses were performed using Statistical Package for the Social Sciences software (SPSS), including Spearman's rho correlation coefficient, Friedman's two-way Analysis Of Variance (ANOVA) for comparison of distributions; bias was compared by way of mean and standard deviation.

RESULTS

The CellaVision reticulocyte counts correlated most strongly with those of the analyzer (often considered the benchmark test); the reticulocyte count distributions were noted not to be significantly different from each other across all three methods. The mean and standard deviation of bias were lowest in the comparison of CellaVision and LH750 counts.

CONCLUSIONS

Our data provide additional support for the accuracy of digital hematology applications using the CellaVision DM96 platform.