Abstract:
BACKGROUND
Automated haematology analysers have become an integral part of the present
day clinical laboratory as they have reduced the number of manual hematology
procedures and increased the speed of reporting without sacrificing the quality of the
results. Manual smear reviews (MSR), however, still play an important role in
identifying morphological abnormalities and to confirm the results of the analysers. It
is thus important to make a decision on whether manual smears are necessary for each
and every sample.
In 2005, the International Society for Laboratory Hematology (ISLH) through
the International Consensus Group for Hematology Review (ICGHR), published 41
rules for peripheral smear review after analysis of samples in AHAs, which were
review criteria for automated blood count analysis in order to reduce the number of
manual smear reviews.
OBJECTIVE
The objective of this study was to evaluate the effectiveness of the ICGHR
criteria for MSR by performing manual peripheral smears for all the samples in the
study group following automated blood cell analysis.
MATERIALS AND METHODS
The study was performed on whole blood samples sent for complete blood
count testing to the central laboratory of the Department of Pathology in B.L.D.E.U.’s
Shri B. M. Patil Medical College, Hospital and Research Centre, Vijayapur. The study
period was from 1st December 2014 to 30th June 2016.Analysis of the blood samples was done on the 6 part differential automated
haematology analyser Sysmex XN-1000 and manual peripheral smear review was
performed along with a 100-cell manual differential count. Each sample was reviewed
according to the adapted ICGHR criteria and the laboratory criteria. Truth tables were
prepared for each set of criteria.
RESULTS
Using the ICGHR criteria, 39.65% samples were true positive, 43.49% were
true negative, 7.91% false positive and 8.95% samples were false negative.
Accordingly the sensitivity was 81.58%, specificity was 84.61%, 83.38% positive
predictive value and, 82.92% negative predictive value. The microscopic smear
review rate was 47.56% with an efficiency of 83.14%.
Our laboratory criteria revealed a true positivity of 48.02%, true negativity of
21.28%, false positivity of 30.12% and a false negativity of 0.58%. The sensitivity
was 98.80%, specificity 41.40%, positive predictive value of 61.46% and, negative
predictive value of 97.34%. The microscopic smear review rate was 78.14% with an
efficiency of 69.30%.
CONCLUSION
There was a significant reduction in the microscopic review rates with the
application of the ICGHR criteria. However, the false negative rate was higher than
the recommended level. Thus the ICGHR criteria can be adapted in laboratories but
must be optimized and locally validated for manual smear review before use.
