Abstract

SICKLE HEMOGLOBIN (EFFECTIVE) DIAGNOSIS INTERFERED BY FALSE POSITIVE AND NEGATIVE RESULTS, DURING FIELD SCREENING BY DTT TEST, CAN BE IMPROVED BY FINDING THE OPTIMUM CONCENTRATION OF SAPONIN AND NA-DITHIONITE

Jignisha S. Patel* and Dr. Jigna P. Naik

Abstract

For field screening of sickle hemoglobin, the first method of choice is Dithionite Tube Test (DTT). DTT test is not 100% sensitive and specific, but its user friendly features make it the first choice for mass screening as well as for routine laboratory testing. For DTT test the buffer solution used contains KH2PO4, K2HPO4, Saponin and Nadithionite. KH2PO4 and K2HPO4 provide buffering effect. Saponin (a mild detergent) act as a lysing agent for RBC and releases hemoglobin which is reduced by a reducing agent Na-dithionite if the released hemoglobin is sickle hemoglobin (HbS). Thus Saponin and Nadithionite play significant role in DTT buffer. In this experiment, five different concentration of saponin (0.1, 0.2, 0.3, 0.4, and 0.5 gm) and six different concentration of Na-dithionite (0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 gm) were used along with fixed concentration of KH2PO4 (16.9 gm) and K2HPO4 (21.5 gm) for 100 mL of DTT buffer solution. As a result, total thirty different DTT buffer solutions were prepared. This experiment was performed to establish the optimum concentration of saponin and Nadithionite in DTT buffer to increase the sensitivity and specificity of test results. Out of 30 different DTT buffer compositions, one composition gave the most desired results and was recommended to be used for mass screening of HbS for effective diagnosis.

Keywords: Sickle hemoglobin (HbS), Screening Test, Dithionite Tube (DTT) Test, DTT Buffer, Saponin, Na-Dithionite.