Tweaking the ISLH Slide Making Criteria- Is it worth?

Abstract

 BACKGROUND: Every laboratory is trying its best to release the report in shortest possible time without compromising its quality. In this era, automated analyzer plays a very important role but manual microscopic review of stained blood film is mandatory to identify morphological abnormalities and to authenticate the results of the analyzer. The aim is to evaluate efficacy of our laboratory criteria using automated analyzer for manual peripheral smear review and to reduce the number of samples requiring microscopic blood film review  METHODS-Retrospective study was done on total 526 patients whose samples were collected over a period of 36 months for complete blood count randomly from both inpatient and outpatient population. Based on our experience we have set our slide making criteria which are more stringent than ISLH. We have taken the study population which falls in the range between ISLH criteria and our lab criteria for study. We made comparisons of adapted ISLH criteria with study population laboratory criteria. RESULTS-   Thus, after employing strict screening criteria the yield of true positives was significantly lower than internationally accepted ISLH criteria (Two sample test of proportion, p value < 0.001).                                                                                                                                                             CONCLUSION- The 41 rules of ISLH for slide review of automated CBC and WBC differential were compared with our study population lab criteria. There was significant reduction in microscopic smear review rate using ISLH criteria. False positive rates are high if cut offs are very narrow. Thus, it was found that tweaking ISLH criteria was an unnecessary exercise.