Comparison between conventional tube method and gel card technique for blood crossmatching: A study in a tertiary care center of north India

Abstract

The cross-matching of blood can be performed by various methods like saline tube method and gel card technique. Saline tube method is most commonly used in blood banks, whereas the latest method used is Gel card technique for cross-matching. Both techniques have their advantages and disadvantages. The main aim of this study was the comparison of gel card and conventional tube test for sensitivity and specificity, time and efficacy. This prospective study was done at the Department of Blood Transfusion, BPS GMC Khanpur Kalan, Sonipat, Haryana. A total of 500 samples collected at the Department of Blood Transfusion, were cross-matched using conventional tube method (spin tube method) with and without using AHG and Gel card Method. 497 (99.4%) samples were compatible, and 3 (0.6%) samples were incompatible with Gel card method, but by test tube method 492 (98.4%) samples were consistent, and 05(1.6%) were false positive (FP). Incompatibility of those 05 samples (FP) disappeared after incubation with AHG reagent at 37°C saline tube method. The sensitivity and specificity of both gel card method and saline tube method with AHG methods is 100% whereas the specificity of saline tube method without AHG is 98.9%. The average time taken by Gel card method was 20-30 minutes for a single compatibility test whereas in conventional spin tube method with the use of AHG (IAT) average time required was 90 minutes and without AHG it was 45-60minutes. The sensitivity and specificity of the spin tube method and the gel card method are comparable to each other. But the gel card method is easy to perform, rapid, reliable procedure and results can be recorded. In contrast, spin saline tube method is more time consuming, and results cannot be preserved. Thus gel card technique can be preferred over the spin tube method.