【讨论】关于微生物验证的一句话翻译

或者是不是指不超过规定值的2倍?

The following is quoted from https://www.edqm.eu/en/page_630.php?rubrique=400 for your reference:

Question-
In Ph. Eur. section 2.6.12 under 4-4 GROWTH PROMOTION OF THE MEDIA. There is a statement that reads ''For solid media, growth obtained must not differ by a factor greater than 2 from the calculated value for a standardised inoculum''. Does the statement mean that the difference can be twice the calculated value of inoculum, or half the calculated value of inoculum?

Answer-
Your interpretation is correct. If the inoculum is 100 CFU then the recovery must be between 50 and 200 CFU.

For further information, please try to search with the keywords “not differ by a factor greater than” (with quotation mark)

2是个比值，意思是50%以上的回收率可以接受

也就是说这里的factor既有减少1/2,也有增加2倍的意思,如果回收率规定为100%,则测试结果在50%(100%/2)～200%(100%×2)之间就是合格的了.

原来是这个意思，我也一直都很迷惑
但是中文该怎么说呢？

是啊，我们的SOP里面规定的是回收率在50%-200%质检的视为有效。

可否翻译为“计数不异于两倍因子的计算值”=低于或大于2倍因子的计算值

2倍因子有这种特定说法吗？

真难用一句话进行准确的翻译，这样翻译是否可行：
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如果所测微生物数的加样回收率在规定值的一半至2倍之间，则该方法是有效的。