Validation of Criteria for Smear Review Following Automated Blood Cell Analysis in Ain Shams University Laboratory
Raghda El Sayed Abd El Monem Galal;
Abstract
Summary
S
ince the first use of automated analyzers, microscopic examination of a stained blood film has complemented analyzer results to provide a comprehensive hematology report on a patient's blood sample. Despite improving capabilities of automated hematology analyzers, manual slide review is still necessary to identify some morphologic abnormalities that may be relatively unremarkable in automated methods.
In 2005, the International Society for Laboratory Hematology through the International Consensus Group for Hematology Review published a set of 41 rules applicable as criteria for the review of automated complete blood counts and leukocyte differential results of automated hematology analyzers, i.e., review criteria for automated complete blood counts.
These guidelines were formulated with the aims of reducing costs and the turnaround time of the results without sacrificing their quality, and justifying the performance and skills of the multiparametric hematology analyzers. Since then, the rules suggested by the Consensus Group have been considered the international standard to indicate situations requiring a blood smear review.
The aim of the present work is to validate and compare the performance of the criteria for smear review suggested by the International Consensus Group for Hematology Review in 2005 with the laboratory criteria currently used in the main laboratory of Ain shams UniversityHospital.
The study samples were routine inpatient samples from all departments of Internal Medicine Hospital except for Hematology Oncology Department which has a dedicated laboratory.
800 blood samples were selected randomly from the daily workload over a period of 3 months.Automated CBC and white blood cell differential counts were performed using Beckman Coulter LH750. Blood films were done for all samples blindly (without knowing the results generated by the analyzer). All samples were reviewed for positive smear findings as identified by the International Consensus Group. 434 (54.25%) samples had positive smear findings.
Among the positive samples, 370 (52.63 %) had RBC abnormalities, 98 (13.94%) had WBC abnormalities, 154 (21.90%) had PLT abnormalities, 40 (5.68 %) had both RBC and PLT abnormalities, 20 (2.84 %) had both RBC and WBC abnormalities, 15 (2.13 %) had both WBC and PLT abnormalities, and 6 (0.85 %) had RBC, WBC, and PLT abnormalities.
That RBCs abnormalities were the top cause of positive smear findings was expected and can be explained by the type of patients involved in the study, besides the prevalence of anemia in the population in general. The commonest findings were microcytosis and hypochromia.
The 2 sets of criteria (the Consensus Group and our laboratory criteria) were applied on the samples, with some adaptations done to the Consensus Group criteria as exclusion of neonates, children and delta check rules. Actually, our laboratory does not receive samples from children or neonates for CBC and it was not possible to implement delta check rules because of limitations of the electronic hospital records.
After defining which samples would have required smear review according to the criteria; the results were compared to the actual findings of the peripheral blood smear to classify samples into true positives, false positives, true negatives and false negatives.
If a rule was triggered and the smear result was positive, the sample was graded as a ‘‘true positive.’’ If a rule was triggered and the smear did not have any positive findings, the sample was graded as a ‘‘false positive.’’ If a rule was not triggered and the smear result was negative, the sample was graded as a ‘‘true negative.’’ If a rule was not triggered but the smear contained a positive finding, the sample was graded as a ‘‘false negative.’’ This was done for both sets of criteria.
The review rate in the present study was high in both sets of criteria (54.25% with Consensus Group and 71% with our laboratory criteria). The high review rate can be explained by that the laboratory serves a tertiary care, big university hospital. Samples were collected from inpatient cases admitted in the hospital which are more liable to abnormal CBCs that trigger the rules for smear review. Moreover, delta check rules were not available in our laboratory so that all samples were considered first time samples.
S
ince the first use of automated analyzers, microscopic examination of a stained blood film has complemented analyzer results to provide a comprehensive hematology report on a patient's blood sample. Despite improving capabilities of automated hematology analyzers, manual slide review is still necessary to identify some morphologic abnormalities that may be relatively unremarkable in automated methods.
In 2005, the International Society for Laboratory Hematology through the International Consensus Group for Hematology Review published a set of 41 rules applicable as criteria for the review of automated complete blood counts and leukocyte differential results of automated hematology analyzers, i.e., review criteria for automated complete blood counts.
These guidelines were formulated with the aims of reducing costs and the turnaround time of the results without sacrificing their quality, and justifying the performance and skills of the multiparametric hematology analyzers. Since then, the rules suggested by the Consensus Group have been considered the international standard to indicate situations requiring a blood smear review.
The aim of the present work is to validate and compare the performance of the criteria for smear review suggested by the International Consensus Group for Hematology Review in 2005 with the laboratory criteria currently used in the main laboratory of Ain shams UniversityHospital.
The study samples were routine inpatient samples from all departments of Internal Medicine Hospital except for Hematology Oncology Department which has a dedicated laboratory.
800 blood samples were selected randomly from the daily workload over a period of 3 months.Automated CBC and white blood cell differential counts were performed using Beckman Coulter LH750. Blood films were done for all samples blindly (without knowing the results generated by the analyzer). All samples were reviewed for positive smear findings as identified by the International Consensus Group. 434 (54.25%) samples had positive smear findings.
Among the positive samples, 370 (52.63 %) had RBC abnormalities, 98 (13.94%) had WBC abnormalities, 154 (21.90%) had PLT abnormalities, 40 (5.68 %) had both RBC and PLT abnormalities, 20 (2.84 %) had both RBC and WBC abnormalities, 15 (2.13 %) had both WBC and PLT abnormalities, and 6 (0.85 %) had RBC, WBC, and PLT abnormalities.
That RBCs abnormalities were the top cause of positive smear findings was expected and can be explained by the type of patients involved in the study, besides the prevalence of anemia in the population in general. The commonest findings were microcytosis and hypochromia.
The 2 sets of criteria (the Consensus Group and our laboratory criteria) were applied on the samples, with some adaptations done to the Consensus Group criteria as exclusion of neonates, children and delta check rules. Actually, our laboratory does not receive samples from children or neonates for CBC and it was not possible to implement delta check rules because of limitations of the electronic hospital records.
After defining which samples would have required smear review according to the criteria; the results were compared to the actual findings of the peripheral blood smear to classify samples into true positives, false positives, true negatives and false negatives.
If a rule was triggered and the smear result was positive, the sample was graded as a ‘‘true positive.’’ If a rule was triggered and the smear did not have any positive findings, the sample was graded as a ‘‘false positive.’’ If a rule was not triggered and the smear result was negative, the sample was graded as a ‘‘true negative.’’ If a rule was not triggered but the smear contained a positive finding, the sample was graded as a ‘‘false negative.’’ This was done for both sets of criteria.
The review rate in the present study was high in both sets of criteria (54.25% with Consensus Group and 71% with our laboratory criteria). The high review rate can be explained by that the laboratory serves a tertiary care, big university hospital. Samples were collected from inpatient cases admitted in the hospital which are more liable to abnormal CBCs that trigger the rules for smear review. Moreover, delta check rules were not available in our laboratory so that all samples were considered first time samples.
Other data
| Title | Validation of Criteria for Smear Review Following Automated Blood Cell Analysis in Ain Shams University Laboratory | Other Titles | التحقق من معاييرمراجعة أفلام الدم بعدالتحليل الآلي لخلايا الدم في مختبر جامعة عين شمس | Authors | Raghda El Sayed Abd El Monem Galal | Issue Date | 2015 |
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