Abstract |
To assess the analytic performance of immunoradiometric
TSH assay (IRMA TSH), assay preci- sion determined by
intra and interassay variance, assay accuracy
determined by dilution and recovery study, were
evaluated by using two commercial kit (Abott and
Daichi). Normal range of basal serum TSH and TRH
stimulated TSH increment were also determined in 234
healthy subjects (male 110, femaie 124; age 20-70) and
30 voluteers (male 10, female 20; age 21-26). In
addition, basal TSH levels of 70 patients with
untreated hyperthyroidisrn, 50 untreated
hypothyroidism, and 60 euthyroidis- m were measured to
assess the clinical utility of IRMA TSH. The detection
limit of IRMA TSH was 0.04 mU/l and 0.08 mU/l by Abott
Kit and Daichi kit respectively. Using Abott kit,
intraassay variance were 2.0, 3.1 and 1.4% in mean TSH
concentration 2.4, 31.6 and 98.2 mU/l repectively and
interassay variance were 2.0 and 3.2% in mean TSH
concentra- tion 2.3 and 31.3 mU/l. Mean recovery rate
was 92.5% and dilution study showed nearly straight
line, When Daichi kit was used, intrasssay variance
were 5.6, 5.2 and 6.2% in mean TSH concentration of
2.4, 31.6 and 98.2 mU/1 respectively and interassay
variance were 7.1 and 7.4% in mean TSH of 2.3 and 31.3
mU,/l. Mean recoveray rate was 89.9%. Norrnal range of
basal TSH and TRH stimulated peak TSH were 0.38-4,02
mU/1 and 2.85-30,8 mU/1 repectively (95% confidence
interval, Abott kit used). Sensitivity and specificity
of basal TSH levels for diagnosing hypothyroidism as
well as specificity for diagnosing hyperthyroidism were
100% by using both kit. Sensitivity of basal TSH level
for diagnosing hyperthyroidism was 100% when TSH levels
were measured by Abott kit while that was 80.9% when
measured by Daichi kit. 'I'hese results suggest that
IRMA TSH was very precise and accurate method and might
be used as a first line test in the evaluation of
thyroid function. |