HBV DNA的新单位国界标准单位

liver411

联合国世界卫生组织, 世界卫生组织生物统一化专家委员会, 为了统一方便计算. 最近规定设立了HBV DNA的WHO HBV国界标准, 单位为"国际单位/毫升--IU/mL. (The WHO HBV International Standard). 和其它标准一样, 它是根据ARUP实验室发明的Real Time PCR 中的TaqMan^TM, ( HBV DNA by TaqMan^TM ), 方法设立. 单位设立分配滴度为1,000,.000国际单位/毫升(IU/mL). 它是在和罗氏分子系统公司同意和他们的检查方法有沟通(Roche Molecular Systems, Inc)下推出. (和通常一样, 是根据HBV基因A型中亚基因型adw2为基础的病毒HBV DNA检查)

ARUP实验室的TaqMan方法对于HBV有分析特异性, 检查率高于99%. 有部分患者在其它地方方法检查阴性, 此方法检查可能为阳性(大约1%). 结果在这些因为其病毒含量在40-600IU/mL(200-300拷贝/mL)更为有效益. 所以分析单项结果需要细心. 这个方法的分析衡量范围在1.6到8.3 HBV DNA log IU/mL (相当于40-200,000,000 HBV DNA IU/mL), 大约合2.3到9.0 HBV DNA log 拷贝/mL (合200到1,000,000,000拷贝/mL). 一个pg/mL大约合283,667拷贝/mL.

所以, 和PT, 凝血酶时间, INR国界凝血酶时间比, 乙肝五项种的s/co(样本/分界值)一样, WHO也规定了HBV DNA的国际单位. 统一化, 这样无论那种方法, 地区检查的结果都可以统一化.它可以不通过FDA核准, 很多研究单位在用(因为文献数据国际化), 但是FDA可能也会很快放入临床使用.

这样HBV DNA可以从 pg/mL, copies/mL, log copies/mL, log IU/mL...统一为IU/mL. 现在看有些昏头, 过一阵子习惯了就好了. 可能国内也会很快使用了(因为很多试剂和仪器, 方法是进口), 因为它的灵敏度在200copies/mL以下.

Real-Time Polymerase Chain Reaction

Assay methodology is real-time PCR using Cobas TaqMan^TM HBV ASR test from Roche Diagnostics Corporation. This is a nucleic acid amplification test for the quantitation of hepatitis B virus DNA in human serum or plasma. The Cobas TaqMan^TM HBV ASR test utilizes real-time TaqMan^TM polymerase chain reaction (PCR) amplification for the detection of HBV DNA. HBV DNA is isolated from patient specimens using an automated robotic platform and is amplified and detected using TaqMan^TM PCR chemistry. Quantitation of HBV DNA is accomplished by using a quantitation standard of a known copy number, which is incorporated into each sample. The quantitation standard is carried through all steps of the assay, including extraction, amplification, and detection. Detection of PCR amplicons is done using specific probes labeled with different fluorescent dyes that hybridize to PCR product as they are created and are subsequently cleaved, releasing the fluorescent dyes into solution and increasing the total fluorescence of that dye in a given sample. Amplification and detection are performed in real time by monitoring the fluorescence levels using the automated Cobas TaqMan^TM analyzer. The analyzer calculates the levels of HBV DNA in the sample by comparing the fluorescence reading for the HBV target to the fluorescence reading for the quantitation standard of known copy number and comparing the relationship to a previously generated standard curve.

ARUP Laboratories has determined that HBV DNA by TaqMan^TM has an analytic specificity of greater than 99%. Rarely (less than 1%), a patient negative for HBV may test positive on this assay. Results in those cases are usually in the range of 40-600 IU/mL (200-300 HBV copies per mL). Care should be taken when interpreting any single HBV DNA determination. The analytical measurement range of this assay is 1.6 to 8.3 HBV DNA log IU/mL (40 to 200,000,000 HBV DNA IU/mL), which is approximately equivalent to 2.3 to 9.0 HBV DNA log copies/mL (200 to 1,000,000,000 HBV DNA copies/mL). One pg/mL of HBV DNA is equal to 282,667 copies/mL. The International Unit (IU) is the assigned unit designation of the First International Standard for HBV DNA assays by the WHO Expert Committee on Biological Standardization (ECBS). The International Standard was assigned a titer of 1,000,000 IU/mL. The WHO HBV International Standard is a genotype A subtype adw2 isolate. PCR is performed pursuant to an agreement with Roche Molecular Systems, Inc.

changluyazhe

顶

liver411

如果用 olymerase Chain Reaction (PCR) 方法: Copies/mL = IU/mL x 2.7

如果用 Branched DNA(bDNA) 方法: IU/mL = Copies/mL x 5.2.

liver411

比如, 如果结果是19,400,000 IU/ml 就等于= 52,380,000 copies/ml. 之后如果想转换成 log10 IU 或 copies. 这里, 19,400,000 IU/ml = 7.28log10 IU/ml 或 7.71 log10 copies/ml.

a111127

顶！！