Qualitative evaluation of in-house immunoassays of T3, T4 and TSH based on bulk reagents

Increase in the cost of RIA kit assays has led to our attempts to seek cheaper alternates. Assays based on bulk reagents [supplied free of cost by INMOL in collaboration with IAEA] were started in 1988. Statistical and Quality control data on 50, 51 and 52 assay batches of T[3], T[4] and TSH respectively has been collected from the beginning. Cumulative assay parameters show that T[3] and T[4] assays are almost equally precise. TSH assay is most imprecise in the group especially at low concentration levels. The working ranges of T[3] and T[4] assays defined at 10% error limit are quite wide and cover low, medium and high levels of hormones. In TSH the assay working range does not cover levels below 10 micro IU/ml. The variability of curve parameters is similar in this group of assays. Quality control results are most reproducible in T[4] assays with a between batch variability of 11.9%. T[3] and TSH assay results are equally reproducible [20.50% variability]. Overall within assay drift is low in all assays. IQC charts of these assays show occasional significant positive or negative shift of results from mean which might be related to methodological variations of quality among various distributions of reagents. The reproducibility and precision of results could be further improved by harmonizing the future distributions of reagents

Ramadan fasting and thyroid hormone profile

A study comprising 41 males,5 females of the age ranging from 28 to 56 years was conducted during Ramadan of 1989 to compare T[3], T[4] and TSH levels in fasting with the levels of non-fasting conditions. Each individual gave 6 blood samples: One sample was taken 20 days before the onset of Ramadan, 3 samples at different fasting days and last two samples were drawn 23 days and five months after the end of Ramadan, respectively. The results showed a significant gradual rise in TSH throughout the fasting month, although the mean levels remained within normal limits. Pre- Ramadan levels were re-attained well after the end of Ramadan. There was no significant change in T[3] and T[4] levels