Gene Gulati

Changes in Automated Complete Blood Cell Count and Differential Leukocyte Count Results Induced by Storage of Blood at Room Temperature

OBJECTIVE To delineate changes that occur in various parameters of automated complete blood cell count (CBC) and differential leukocyte count (differential) on prolonged storage of blood at room temperature. DESIGN A CBC and an automated differential were performed on the Coulter Gen.S on 40 K(3) (tripotassium ethylenediamine-tetraacetate) EDTA-anticoagulated blood specimens once daily, specimen volume permitting, for 3 to 7 days. Specimens were kept at room temperature throughout the study. The results were tabulated using a personal computer with Excel software. Percent change or absolute difference from the initial value for each parameter for each subsequent day of the study period was calculated. RESULTS Among the CBC parameters, hemoglobin, red blood cell count, and mean corpuscular hemoglobin were stable for the duration of the study (7 days), white blood cell count was stable for at least 3 days (up to 7 days, if the count was within or above the normal range), and platelet count was stable for at least 4 days (up to 7 days, if the count was within or above the normal range). The mean corpuscular volume, mean platelet volume, hematocrit, and red blood cell distribution width each increased, and the mean corpuscular hemoglobin concentration decreased from day 2 onward. Among the differential parameters, the relative percentages and absolute numbers of neutrophils, lymphocytes, and eosinophils tended to increase, whereas those of monocytes trended downward over time. Limited data on basophils did not reveal an appreciable change. CONCLUSION Blood specimens stored at room temperature for more than 1 day (up to 3 days or possibly longer) were found to be acceptable with some limitations for CBC but not for the differential.

International normalized ratio versus plasma levels of coagulation factors in patients on vitamin K antagonist therapy.

CONTEXT The key question when managing patients on warfarin therapy who present with life-threatening bleeding is how to use the international normalized ratio (INR) to best direct corrective therapy. The corollary question for the clinical laboratory is at what level will the INR reflect a critical value that requires notifying the clinician. OBJECTIVE To determine the levels of vitamin K-dependent factors over a range of INR values. DESIGN Evaluation of the vitamin K-dependent coagulation factor levels on plasma remnants from patients in whom a prothrombin time and INR was ordered to monitor warfarin therapy. There were a total of 83 specimens evaluated with an INR range from 1.0 to 8.26. RESULTS The mean activity levels of all 4 factors remained near or above 50% when the INR was less than 1.5. The average factor X level was 23% when the INR range was 1.6 to 2.5, but levels of factors II, VII, and IX did not drop below the hemostatic range until the INR was greater than 2.5. At an INR of 3.6 or more, the activity levels of all 4 factors were less than 30% in more than 90% of the specimens. CONCLUSION Levels of factors II, VII, IX, and X declined with increasing INR but not at the same rate and not to the same level at a given INR. However, most of the values were below the hemostatic value once the INR was 3.6 or more, the level that was also considered critical for physician notification.

An evaluation of the performance of sysmex XE-2100 in enumerating nucleated red cells in peripheral blood

CONTEXT Automated methods of enumerating nucleated red blood cells (NRBCs) in blood are gaining acceptance in many laboratories. OBJECTIVE To evaluate the performance of Sysmex XE-2100 in enumerating NRBCs in peripheral blood. DESIGN Automated relative number of NRBCs per 100 white blood cells (NRBC%) results for a total of 460 specimens run on the XE-2100 were compared with manual NRBC% results obtained by performing a 100-cell differential on a Wright-stained smear prepared from each specimen. To assess within-day reproducibility, 64 specimens were rerun on the XE-2100, and a second 100-cell differential was performed on the original blood smear. Excel software was used for data analysis. RESULTS Regression analysis of automated NRBC% versus manual NRBC% yielded a correlation coefficient of 0.9712. No NRBCs were seen in the blood smear on 35 (15.1%) of 232 specimens with automated NRBC% of 0.1 to 1.9. The XE-2100 generated an NRBC% of 0.0 on 5 (6.8%) of 74 specimens, revealing 1 NRBC per 100 or more white blood cells by blood smear examination. The mean percent difference between duplicate automated results was 16.7 compared with 78.1 for the duplicate manual results. There were 9 instances in which the XE-2100 either did not detect the presence of more than 8 NRBCs per 100 white blood cells or generated an automated NRBC% of 18.1 or 18.8 when the smear revealed none. All of these were, however, flagged for smear review. CONCLUSIONS Overall correlation between the automated and manual results was excellent. The automated method revealed better precision than the manual method. The number of specimens with false automated results was very small, and all were flagged for verification by a smear review.

Purpose and criteria for blood smear scan, blood smear examination, and blood smear review.

A microscopic examination of an appropriately prepared and well-stained blood smear by a knowledgeable laboratory professional is necessary and clinically useful in a number of circumstances and for a variety of reasons. In this article, an attempt is made to delineate the purpose and criteria for blood smear examination in a variety of circumstances that are encountered in everyday laboratory hematology practice. A blood smear scan serves to at least (a) verify the flagged automated hematology results and (b) determine if a manual differential leukocyte count needs to be performed. Blood smear examination/manual differential leukocyte count with complete blood count (CBC) provides the complete hematologic picture of the case, at least from the morphologic standpoint. Blood smear review with or without interpretation serves to ensure that no clinically significant finding is missed, besides providing diagnosis or diagnostic clue(s), particularly if and when interpreted by a physician.

Does Routine Repeat Testing of Critical Values Offer Any Advantage Over Single Testing

CONTEXT Before being communicated to the caregiver, critical laboratory values are verified by repeat testing to ensure their accuracy and to avoid reporting false or erroneous results. OBJECTIVE To determine whether 2 testing runs offered any advantage over a single testing run in ensuring accuracy or in avoiding the reporting of false or erroneous results. DESIGN Within the hematology laboratory, 5 tests were selected: hemoglobin level, white blood cell count, platelet count, prothrombin time, and activated partial thromboplastin time. A minimum of 500 consecutive critical laboratory test values were collected retrospectively for each test category. The absolute value and the percentage of change between the 2 testing runs for each critical value were calculated and averaged for each test category and then compared with our laboratorys preset, acceptable tolerance limits for reruns. RESULTS The mean results obtained for the absolute value and the percentage of change between the testing runs were 0.08 g/dL (1.4%) for hemoglobin levels, 50 cells/µL (10.2%) for white blood cell counts, 1500 cells/µL (9.9%) for platelet counts, 0.7 seconds (1.4%) for prothrombin time, and 5.1 seconds (4.4%) for activated partial thromboplastin time (all within our laboratorys acceptable tolerance limits for reruns). The percentage of specimens with an absolute value or a mean percentage of change outside our laboratorys acceptable tolerance limits for reruns ranged between 0% and 2.2% among the test categories. No false or erroneous results were identified between the 2 testing runs in any category. CONCLUSIONS Routine, repeat testing of critical hemoglobin level, platelet count, white blood cell count, prothrombin time, and activated partial thromboplastin time results did not offer any advantage over a single run.

Effects of Storage of Blood at Room Temperature on Hematologic Parameters Measured on Sysmex XE-2100

Blood specimens are frequently delivered to the clinical laboratory after a significant postcollection interval. On weekends, this interval may exceed 72 hours. When such a specimen arrives, the laboratory must decide whether to accept or reject the specimen. If accepted, the laboratory must then decide whether to perform all of the tests ordered or only those deemed appropriate given the age of the specimen, and what comments should be appended to the reported results regarding the reliability or limitations of the analysis. Storage of K2-EDTA-anticogulated blood at room temperature for up to 4 days caused changes in some but not all hematologic parameters measured on Sysmex XE-2100 analyzer. Specifically, the WBC, RBC, HGB, and PLT were found to be stable for up to 3 days. Retic % and #, but not the IRF, were stable for the duration of the study. Diff results may be unreliable or voted out by the analyzer on specimens that are 2 day old or older. The NRBC counts changed little on the average but revealed consistently wide 95% confidence intervals throughout.

An Assessment of the Coulter Gen•S Automated Flagging System

instrumentation [generalist | hematology | cytology] An Assessment of the Coulter Gen•S Automated Flagging System Gene L. Gulati, PhD,1,2 William Kocher, MD,1,2 Roland Schwarting, MD,1,2 Lawrence J. Hyland, MD,1,2 Ali Issa, BSMT,1 Robert Arwood, BSMT,1 and Manmohan Dhanjal, BSMT(ASCP)SH1 From the 1Hematology Laboratory, Thomas Jefferson University Hospital, and the 2Department of Pathology, Jefferson Medical College, Philadelphia, PA

Automated Lymphocyte Counts vs Manual Lymphocyte Counts in Chronic Lymphocytic Leukemia Patients

Objective: This study was undertaken to determine if automated differential leukocyte counts (A-DIFF) can be used in place of manual differential leukocyte counts (M-DIFF) in chronic lymphocytic leukemia (CLL) patients. Methods: Relative and absolute automated lymphocyte counts obtained from 83 specimens from 76 CLL patients were compared with corresponding manual counts obtained by performing differential on albuminized blood smears. Means and correlation coefficients were calculated using Excel software. Results: The mean relative lymphocyte count by automated method was 73.6% as compared to 75.6% by the manual method. The mean absolute lymphocyte count by automated method was 32.1 × 10 3 /µL as opposed to 32.9 × 10 3 /µL by the manual method. The correlation coefficients were 0.928 and 0.998 for the relative lymphocyte counts and absolute lymphocyte counts, respectively. Conclusion: Automated differential leukocyte counts can be used in place of M-DIFF in CLL.

Optimization of Criteria for Verification of Automated Platelet Counts Generated by the Sysmex XE-2100 Hematology Analyzer

Background Verification of automated platelet counts by blood smear examination is necessary but time consuming. This study was undertaken to optimize the criteria for performing platelet scans. Methods Platelet scans were performed on 796 blood smears made from specimens that were either flagged for (a) platelet abnormal distribution or PAD (group I), (b) platelet clumps or CLP (group II), (c) PAD + CLP (group III), or (d) had a platelet count below 100,000/μL (group IV). Based on the findings of the platelet scans, a percent positive yield was determined for each group of specimens. Results Percent positive yields of 8.9, 30.0, 35.3, and 1.9 were obtained from platelet scan findings for groups I, II, III, and IV, respectively. Conclusions Optimal criteria for performing platelet scans excluded the PAD flag and the follow-up platelet counts below 100,000/μL but included specimens flagged for CLP and the initial platelet counts below 100,000/μL.

Detection of Platelet Clumps on Peripheral Blood Smears by CellaVision DM96 System and Microscopic Review.

OBJECTIVE To determine and optimize the sensitivity of the CellaVision DM96 automated image-analysis system in detecting platelet (PLT) clumps on blood smears and to assess the reliability of the traditional laboratory practice of examining only the feather edge of the smear for PLT clumps. METHODS We processed 102 blood smears that revealed PLT clumps on microscopic review, using the CellaVision DM96, and reviewed the results for the ability of the analyzer to detect these clumps. We obtained the data regarding relative distribution of PLT clumps on different parts of the blood smear (feather edge, lateral edges, and readable area) from our microscopic-review observations. RESULTS The sensitivity of the Cellavision DM96 in detecting PLT clumps was between 40.4% and 82.8%, depending on the number of screens reviewed for this variable. Via microscopic review of the smears, the PLT-clump detection rate increased from 85.3%, obtained by examining only the feather edge, to 99.0%, obtained by examining the feather edge plus the readable area. CONCLUSION The sensitivity of the DM96 for detecting PLT clumps can be maximized to 82.8% by reviewing the entire white blood cell screen and the entire PLT screen. Microscopic review of the blood smears yielded a PLT-clump detection rate of 99.0% when we examined the feather edge and the readable area of the smear.