Serum tirotropin için biyolojik varyasyon bileşenleri ve kalite spesifikasyonlarının belirlenmesi
Amaç: Serum tiroid hormon düzeyleri tiroid hastalıklarının tanı ve takibinde kullanılır. Bu çalışma serum tirotropin (TSH) için biyolojik varyasyonu (BV) hesaplanması ve değerlendirilmesini amaçlamaktadır.Gereç ve yöntemler: Kan örnekleri, sekiz gönüllüden (dört kadın, dört erkek; yaşları 20-35 arasında değişen) beş hafta boyunca, haftalık olarak alındı. Serum TSH seviyeleri Abbott Architect ci8200 immunassay cihazında ölçüldü ve Biyolojik varyasyon (BV) hesaplamaları Fraser’ın yöntemine göre nested ANOVA testi kullanıldı. Bulgular: Serum TSH için hesaplanan analitik varyasyon (CVA), birey içi BV (CVI), bireylerarası BV (CVG), bireysellik indeksi (II) ve referans değişim değeri (RCV) değerleri sırasıyla % 5.4, % 26.2, % 26.9, 0.99 ve % 74.2 idi. Belirsizlik, bias ve izin verilen toplam hata (TEA) için istenen performans hedefleri sırasıyla <% 13.1, <% 6.7 ve <% 28.3 idi. Sonuç: BV veri tabanındaki (CVI =% 19.3 ve CVG =% 24.6) sonuçlar ile karşılaştırdığımızda Serum TSH için elde ettiğimiz CVI ve CVG değerleri daha yüksek olduğunu tespit ettik. TSH’ın takibi sırasında sonuçların değerlendirilmesi için hesaplanan düşük II, TSH bireyselliğinin daha belirgin olduğunu ve toplum bazlı referans aralıklarının daha az kullanışlı olduğunu gösterir.
Determination of biological variation components and quality specifications for serum thyrotropin
Purpose: Serum thyroid hormone levels are used in the diagnosis and follow-up of thyroid disorders. The present study aims calculation and evaluation of biological variation (BV) measures for serum thyrotropin (TSH). Materials and Methods: Blood samples were collected from eight volunteers (four women, four men; ages ranging between 20 to 35) weekly throughout five weeks. Serum TSH level was measured on Architect ci8200 immunoassay system and BV estimates were obtained using nested ANOVA test according to the method of Fraser. Results: Calculated analytical variation (CVA), within-subject BV (CVI), between-subject BV (CVG), index of individuality (II) and reference change value (RCV) for serum TSH were 5.4%, 26.2%, 26.9%, 0.99 and 74.2%, respectively. Desirable performance goals for imprecision, bias and total allowable error (TEA) were <13.1% , <6.7% and <28.3% respectively. Conclusion: When we compared our results with the results from BV database (CVI=%19.3 and CVG=%24.6) for serum TSH we found out higher CVI and CVG values. Calculated low II meaning marked individuality indicates that population-based reference values are less useful for the evaluation of results while monitoring serum TSH.
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