Results of Reentry Test for the Deferred Donors after Non-Discriminated Reactive in Nucleic Acid Amplification Test / 대한수혈학회지

BACKGROUND: Since December 15 2017, donors showing a non-discriminated reactive (NDR) result in the nucleic acid amplification test (NAT) have been temporarily deferred and anti-HBc and anti-HBs assays as additional tests were performed. Donors with an anti-HBc reactive result and less than 100 IU/L of anti-HBs could not be released and can request a reentry test after more than six months. This study considered the effects of additional tests for NDR donors by analyzing the reentry test results in donors not released in the additional test. METHODS: This study examined the results of the additional test for NDR donors from January 2017 to September 2018 and the reentry test of the donors not released in the additional test. RESULTS: NAT was conducted on 4,706,051 blood donors over the period and 2,545 (0.05%) of them showed NDR. A total of 656 (25.8%) of the NDR donors were not released in the additional test. Among them, 246 donors requested a reentry test; 222 (90.2%) donors were not reentered, and 23 (10.4%) showed HBV NAT reactive results in the reentry test. Among the remaining 24 reentered donors, 2 donors (8.3%) showed anti-HBc nonreactive results in the reentry test and 22 donors (91.7%) showed higher than 100 IU/L of anti-HBs. CONCLUSION: The follow-up of NDR donors may be significant because some donors showed different results between screening test and reentry test. In addition the effectiveness of the introduction of additional tests for the NDR donors has been proved to be effective.

An Analytical Study of Retesting of Retained Sample Results.

Aims: The sample retention policy for Clinical Chemistry analytes in accredited medical laboratories as per ISO 15189:2012 is 24 hrs. Serum/ plasma to be separated in aliquot within 20 minutes of collection unless the primary containers are gel vacutainers. Rigorous maintenance of such procedure is difficult and as a result the possibility of deviation from such schedule may not be very uncommon. The 1 year Turn Around Time (TAT) analysis of the laboratory is a good guide to find out time lag from sample collection to sample processing & average time of collecting samples in aliquot for retained sample testing. The laboratory retested 22 common analytes on the basis of such time lag and evaluated the deviation from 1st observation. The accumulated data has helped to evaluate and implement sample retention policy. Study Design: The average time lag from collection to completion of test performance of a batch is 4hrs± 30 minutes. The analytes were retested in the time lag. After accumulation of sufficient data the time lag increased to 6 hours±30 minutes which is the average lag from sample collection to end of the day duty personnel. In the 3rd phase total retention time ie, 24 hrs has been considered as time interval of retained sample retesting. But the samples remained at room temperature for 6hrs±30minutes before being preserved at 2°C-8°C. Hence time lag was (6hrs±30min) at room temperature and 17hrs ±30min at 2°C-8°C. The samples always retested from primary container. Place and Duration of Study: The study took place in JMD Diagnostics Private Limited, Kolkata, India. The duration of study is 2 yrs. Methodology: The analytes were tested in Cobas Integra 400plus system. The tests have been performed as routine tests and considered as 1st observation. 2nd observation values obtained after the specified time lag. The results obtained were compared using statistical software. Comparison of 1st and 2nd results and bias of all analytes were studied. Electrolytes have been eliminated from the study as the electrolytes are preferred to be retested from freshly collected sample. Labile parameters like L-Lactate, ammonia, bicarbonate were also not considered for the same reason. Conclusion: Only 3 analytes, total protein, total calcium and inorganic phosphorus cannot be preserved in primary containers. The analytes also need not to be separated within 20 minutes of collection. Upto 4hrs±30 minutes all the parameters have shown excellent correlation coefficient. Hence, the laboratory earns a time lag between collection to preservation of samples for these analytes. For other 19 analytes sample may be kept in primary container.