Finish before the start: Analyzing preanalytical sample errors in a tertiary care hematology laboratory.

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.