求解表面抗原稀释实验

music000

又查了一下：

（1）：http://www.kenes.com/easl2010/posters/Abstract613.htm

这里说：Methods: 127 patients followed for a median period of 6 years (0.5 to 18), 102 inactive-carriers (n=102) and 25 HBeAg-negative CHB patients, were evaluated. Serum HBsAg was quantified using the Elecsys HBsAg II assay. Samples were tested at 1:400 dilution. If result revealed cut off index (c.o.i.) of > 1, then the final result is c.o.i. 400. If c.o.i. < 1, then the sample is retested undiluted and final result is result of retest (c.o.i.). If c.o.i. ≥ 1000, then the sample is retested at 1:8000 dilution and final result is c.o.i. 8000. HBsAg was estimated using a conversion factor of 1 c.o.i. = 0.055 IU/mL.

（2）：http://www.natap.org/2009/APASL/APASL_02.htm

Methods:
HBsAg was quantified using the Architect® HBsAg assay (Abbott Laboratories; dynamic range 0.05-250.0 IU/mL, WHO standard) and the Elecsys HBsAg II dilution algorithm (standardized to WHO standard 00-588, conversion factor for estimation of HBsAg units: coi of 1 = 0.064 IU/ml).

（3）：http://www.natap.org/2008/AASLD/AASLD_51.htm


上面这个图说明，IU与COI成线性关系（应该是在一定条件下）。

所以，以前战友所预测的，1 IU/ml 约等于＝18 COI 是对的。

music000

知道了罗氏检测的情况后，下一步就是：  S抗原定量检测到底对乙患有没有意义。

1， 如果有意义，并且象王医生所说的，（大三阳的）可提前（六个月）预测耐药，这六个月对患者来说重不重要。换句话说，个体已发生了六个月的耐药情况而未做处理，对今后发生肝硬化和HCC有没有决定性的意义。

我觉得定量检测对停药的预测还是有帮助的。

2. 我们同时要关注国外定量检测的动态。

3.  我看到王医生给战友做的稀释结果，举例：

     在化验单上某战友的COI 结果为　475.7，王医生让乘200，结果是9.5万，所以那个单子上真正的COI应该是9.5万吧？
     所以，我看大家在另一个贴子中说，大于1万停药会失败，这个1万就是指COI，不知对不对。

4.  不知我的想法合不合理 。  请大家指正。
   王医生，我找的东东对不对？你如果愿意可以给大家解释下COI的意思，先谢谢了

StephenW

music000 发表于 2011-11-4 13:42
又查了一下：

（1）：http://www.kenes.com/easl2010/posters/Abstract613.htm

补充一点:

"HBsAg was quantified using the Architect® HBsAg assay (Abbott Laboratories; dynamic range 0.05-250.0 IU/mL, WHO standard) " - Architect是一个定量(quantative)检测
and the Elecsys HBsAg II dilution algorithm (standardized to WHO standard 00-588, conversion factor for estimation of HBsAg units: coi of 1 = 0.064 IU/ml). -罗氏Elecsys是一种定性(qualitative)检测，但可以作为定量的使用.

"We have previously shown that this assay, currently available as a qualitative assay for HBsAg, can be used effectively for the quantification of HBsAg levels using a simple dilution algorithm (see methods section)8."
我们先前已经表明，这个检测(Roche Elecsys)，目前为乙肝表面抗原定性检测，可以有效地用于HBsAg水平的量化, 使用一个简单的稀释算法（见方法部分）8。

1.conversion factor for estimation of HBsAg units: coi of 1 = 0.064 IU/ml
coi of 1 = 0.064 IU/ml  - not 1 coi = 0.064 IU/ml , i.e. 1 IU/ml = coi of 15.625


2. HBsAg was estimated using a conversion factor of 1 c.o.i. = 0.055 IU/mL.
i.e. 1 IU/ml = coi of 18.181

你使用哪一个: 15.625 or 18.181?

music000

我觉得它们之间有比例关系，这就行了。我本人觉得罗氏检测对我自己的病情作用不很大，所以，具体数不是很在意了；

还有一个原因，这类检测关系到“回归方程”，数学我最差了，所以，我个人觉得，罗氏检测的误差很大，差个几千甚至几万的都难说啊。雅培的半定量就足够了。  

StephenW

music000 发表于 2011-11-4 17:04
我觉得它们之间有比例关系，这就行了。我本人觉得罗氏检测对我自己的病情作用不很大，所以，具体数不是很在 ...

"还有一个原因，这类检测关系到“回归方程”，数学我最差了，所以，我个人觉得，罗氏检测的误差很大，差个几千甚至几万的都难说啊。雅培的半定量就足够了。"

罗氏(Elecsys HBsAg II assay)检测是半定量(semi quantitative). 雅培(Architect) 是定量(quantitative).

P.S. 罗氏公司有一个新的定量乙肝表面抗原检测系统(Elecsys HBsAg II quant assay)。这一个是准确的定量检测。
Multicenter Evaluation of the Elecsys® HBsAg II Quant Assay
http://www.natap.org/2011/APSL/APSL_05.htm
The Elecsys HBsAg II quant assay reliably quantified HBsAg in routine clinical samples across all major HBV genotypes encountered globally, and at all stages of infection tested, including in sera with high HBsAg levels (up to 873,300 IU/mL).

The assay gave exact results over a broad linear range (0.05-52,000 IU/mL) reflecting clinically relevant HBsAg titers, and is optimized to reliably quantify HBsAg in samples encountered in clinical practice.

The defined onboard dilution step reduces the need for retesting; more than 70% of the samples gave a final result on first analysis.

Onboard dilution reduces the potential for pipetting errors, lowers "hands-on" time and saves costs. Onboard reagents are stable for up to 8 weeks, improving convenience and reducing waste.

The assay showed high precision across the entire measuring range. The high precision of the assay is particularly important if serum HBsAg titers are to be compared between different samples from the same patient, for example, during on-treatment monitoring.

The Elecsys HBsAg II quant assay is standardized against the WHO Second International Standard for HBsAg, ensuring the reliability of HBsAg values. This is important when comparing values between different laboratories.

The Elecsys HBsAg II quant assay is highly suitable for the quantification of HBsAg levels in routine clinical samples, providing accurate, standardized results for clinical decision making.