2014, Cilt 12, Sayı 2, Sayfa(lar) 065-072 |
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Can Automated Immunassays be Used Instead of Manual Analysis for TRab Analysis? |
Ferhat Demirci1, Barış Sağlam1, Pınar Akan1, Dilek Çımrın2 |
1Dokuz Eylül Üniversitesi Tıp Fakültesi, Tıbbi Biyokimya AD, İzmir, Türkiye 2Dokuz Eylül Üniversite Hastanesi, Merkez Laboratuvarı, İzmir, Türkiye |
Keywords: Thyroid Stimulating Hormone Receptor; methodological study; comparative studies; Graves' Disease |
Objective: Graves' disease is an autoimmune disease which results in excessive production of thyroid
hormones and is the most common cause of hyperthyroidism. TRAb has a key role to confirm the
clinical diagnosis of Graves' disease. The different measurement methods have been developed because of the different bioactivity types of these antibodies. Radioimmunoassay (RIA) is the
recommended method of measurement in Graves' diagnostic guidelines. Recently, use of immunebased
automated methods instead of manually RIA measurement is discussed. In our study, we aimed
to compare the availabilities of automated immunoassay and manual RIA methods for TRAb analysis.
Materials and Methods: According to “Patient Based Comparison Methods of Clinical Laboratory
Standards Institute”, the serum samples of 55 patients were analyzed by RIA and ECLIA methods. The
systematic and random error rates were determined for both methods. The method's validities were
evaluated for medical decision criterions.
Results: While total error (TE) of the RIA method was 19.81 (%), TE rate of ECLIA method was 41.6 (%).
According to regression analysis, the correlation between two methods was good level (r = 0.8). At the
lower levels of TRAb, the differences between RIA and ECLIA were higher than the others. When
borderline test results were evaluated as any thyroid disease except Graves'; the negative predictive
value of ECLIA method was 97.8 (%), the validity of the test was 94.3 (%).
Conclusion: ECLIA method may be preferable for routine TRAb analysis to diagnosis Graves' disease,
although it has high total error rate compared to RIA. It has high diagnostic validity and negative
predictive values. It is known that automated methods may have lower random error compared to
manual methods. On the other hand, the cost effectiveness of automated ECLIA method should be
evaluated because of its requirements such as analyzer and supplies.
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