比較直接計測與手工稀釋放射免疫分析尿自蛋自濃度

背景：糖尿病病人的腎併發症可藉由檢測微白蛋白尿(microalbuminuria)及早被發現而得到適當的控制，本實驗室所使用試劑為競爭性放射免疫分析方法(RIA: Double Antibody Albumin)，檢測範圍是5-60μg/ml，大於60μg/ml的尿液檢體需使用0μg/ml標準液稀釋完後再分析，本研究是比較一種替代方法與傳統手工稀釋方法結果的相關性。方法：利用直接計測的方式將最高校正(calibrator)濃度提升到120μg/ml，然後將原來最高的校正液(calibrator)60μg/ml和提高的校正液120μg/ml作0倍、2倍、4倍、8倍以及16倍的連續稀釋求出回收率（觀察值／期望值）。再利用已分析完畢冷凍保存的尿液檢體，隨機取出30支原來數據落在60-120μg/ml區間，然後使用直接計測法(direct assay)和手工稀釋法(dilute assay)比較分析計測結果。結果：校正液濃度60μg/ml和120μg/ml回收率分別為103%和97%，三次測量的截距點(Intercept point) ED20、ED50和ED80之平均值與CV值分別為65.91±1.51μg/ml、2.28%、18.3±0.15μg/ml、0.02%、5.57±0.38μg/ml、0.14%。30支尿液檢體的直接計測法和稀釋法其平均值分別為104.34、111.86，作線性迴歸統計分析R^2=0.93，二者有直線相關。結論：檢查尿液中白蛋白(albumin)時將校正液(calibrator)高濃度點由60μg/ml增設到120μg/ml後，每月平均受檢人數中須稀釋的檢體量可降10%左右（從28.6%降至18.6%），使整個年度的稀釋累積人數約少500個檢體，此方式在0μg/ml calibrator的使用、報告的速度以及人力、耗材、時間各方面的考量可有效的應用。

關鍵字

放射免疫分析方法；微白蛋白尿；校正液；截距點

並列摘要

Background: Microalbuminuria is a condition characterized by increased urinary excretion of albumin in the absence of overt nephropathy. Methods: In our radioimmunoassay laboratory, the calibration ranges for the radioimmunoassay (RIA: Double Antibody Albumin) were 5 to 60μg/ml, data greater than the highest calibrator ranges should be diluted in zero calibrator. Thirty urinary samples collected from diabetic patients with albumin values greater than the highest calibrator were used to compare the efficacy and linearity between the direct method and the dilution methods. Results: Measurements of 60μg/ml and 120μg/ml calibrator percentage recovery were 103.7% and 97.6% with difference less than 5% each. Three measured intercept point for ED20, ED50 and ED80 were 65.91 ± 1.51, 18.30 ± 0.15 and 5.57 ± 0.38 respectively. The mean values of thirty urine samples using direct count and manually dilute methods were 104.3 and 111.9 respectively with a correlation coefficient of 0.97, and linear regression R^2 of 0.93. When adjust the highest calibrator from 60μg/ml to 120μg/ml, the averaged monthly sample amount needed to be diluted dropped from 28.6% to 18.6% (about 10% decreased). Conclusion: Using change of the highest calibrator from 60μg/ml to 120μg/ml, we can save zero calibrator, time, manpower and cost.

並列關鍵字

RIA ； microalbuminuria ； calibrator ； intercept point

國際替代計量

比較直接計測與手工稀釋放射免疫分析尿自蛋自濃度

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