A Validation Study of After Reconstitution Stability of Diabetes: Level 1 and Diabetes Level 2 Controls

The after reconstitution stability of L1 & L2 is 7 days when stored at 2°-8°c and tightly capped. The total content of the vial is 500 µL and per test requirement is 5 µL. Hence, in 7 days laboratories would consume only 35 µL wasting 365 µL which is 73% of the expensive control samples and such wastage should be ideally prevented. The study of after reconstitution stability proved the stability of the control samples up to 90 days resulting in proper utilization of L1 & L2.

The L1 & L2 controls were reconstituted using 500 µL deionized water. The vials were allowed to stand for 5-10 minutes, swirled 8-10 times to maintain the homogeneity. Aliquots of 10 µL were prepared. One aliquot of one control level being used per day, both levels on alternate day. 5 µL control is mixed with 1.5 mL diluent and HbA1c was tested in D10 system by HPLC method. Therefore, 500µL may be utilized up to 45 days approximately provided the extended use of control run is not affecting quality of test results. The minimum number of samples tested by the laboratory from a single vial is 45 and maximum 46.

Three lots were tested of which one lot has been tested in two laboratories. Mean, SD, CV%, TAE, %Bias, z-score and sigma calculations were done. The medical method decision charts were created for all lots based upon normalized operational specifications which showed excellent precision in both control levels. Number of rejections in the study was nil.

The extended use of controls is validated.