Aims: (a) To evaluate the types and frequencies of preanalytical errors occurring in a tertiary care hematology diagnostic center and (b) To evaluate differences if any, across groups [outpatient data (OPD) vs inpatient data (IPD), type of test requested [complete blood count (CBC) vs coagulation] and laboratory (routine vs emergency).
Settings and design: A prospective study was conducted over a period of nine months (August 2017-April 2018) to address the above objectives. All samples received in the clinical hematology division of our institute were included in the analysis.
Materials and methods: Categories of preanalytical errors were defined. This included insufficient, clotted, diluted, and lipemic samples. Clerical errors such as wrong/absent sample labeling, requisition form-sample mismatch, and wrong vacutainer selection were also documented. IPD and OPD data, as well as data pertaining to samples sent for different tests [complete blood count (CBC)/coagulation] and in the routine and emergency laboratories, were segregated.
Statistical analysis used: All errors in each category were recorded as numbers and corresponding percentages (proportions). The two-tailed z-test was applied to assess the significance of the difference in proportions across all groups. Statistical significance was kept at P < 0.05.
Results: A total of 189,104 samples were received in the clinical hematology laboratory during the aforementioned period, out of which preanalytical errors were found in 4052 (2.14%) samples. Inadequate sample quantity (ISQ) comprised the bulk of preanalytical errors in our laboratory (1.11% of total samples) followed by sample clots (0.88%). There was no significant difference in the error frequencies in OPD and IPD (P = 0.1031). The proportion of errors was higher in routine vis-à -vis emergency samples and also in samples sent for coagulation analysis vis-à -vis CBC.
Keywords: Error; hematology; laboratory testing; phase; preanalytical.