2017 Volume 66 Issue 1 Pages 25-32
There is no internal quality control (IQC) procedure for counting the percentage of immature granulocytes (IGs) on blood smears. We developed an IQC application to assess an examiner’s performance and to standardize criteria for IG classification. The application allows examiners to decide the cell type on the basis of digital photo images of IGs on computer monitors and quantitatively assesses their performance. We used reference images downloaded from the website of the Japanese Society for Laboratory Hematology (JSLH). Three examiners performed IQC for 70 days. Their results were compared between the first and second half periods (35 days for each period). Next, blood films including IGs were defined as positive for each cell type and interobserver variations were analyzed using the number of positive findings. In the IQC results, the rate of agreements between JSLH and examiners increased. The median was close to 100% and the level of variation decreased in each cell type. In patients’ samples, the level of significance of variation caused by the difference in the examiner could not be statistically confirmed for each cell type except for metamyelocytes (p < 0.01). The IQC improves the accuracy and repeatability of IG classification and suppresses the interobserver variation of recognition of IGs on patients’ smears of clinical blood samples. In this study, we concluded that IQC for IG classification using reference images improves the quality and standardizes the criteria of this test.
