Log in
RegisterAn example of IS response. Need your helps. [Bioanalytics]
Dear Shuanghe,
Agreed.
Agreed.
I would try and understand what happened first, and look at the whole set of information very closely. Anything else that varied here, such as retention times ?
It doesn't look like a subject-specific phenomenon: the QC samples are affected the same way. By the way, how are the results of the last 6 QC samples ? If even the last ones are passing, you could conclude that whatever is happening does not appear to have a large effect on accuracy. I'd still be concerned, until I understand what's going on. The calibration curve is not repeated at the end of the run, so there is no way to check what's happening at the ULOQ, where you may get linearity issues due to detector saturation or ion suppression of the analyte by the IS.
❝ However, from pure bioanalytical point of view, in my opinion, there's clearly something wrong here.
Agreed.
❝ If runs like this are deemed acceptable according to SOP and not even trig an investigation, I don't care what the creteria is, the SOP may need to be revised.
Agreed.
❝ At the least, the samples from 2nd half of the run should be repeated. I would repeat the whole run.
I would try and understand what happened first, and look at the whole set of information very closely. Anything else that varied here, such as retention times ?
It doesn't look like a subject-specific phenomenon: the QC samples are affected the same way. By the way, how are the results of the last 6 QC samples ? If even the last ones are passing, you could conclude that whatever is happening does not appear to have a large effect on accuracy. I'd still be concerned, until I understand what's going on. The calibration curve is not repeated at the end of the run, so there is no way to check what's happening at the ULOQ, where you may get linearity issues due to detector saturation or ion suppression of the analyte by the IS.
—
Regards
Ohlbe
Regards
Ohlbe
Complete thread:
- An example of IS response. Need your helps. Shuanghe 2020-05-26 12:56
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- An example of IS response. Need your helps. Sukalpa Biswas 2020-05-26 13:49
- An example of IS response. Need your helps. Shuanghe 2020-05-26 16:32
- An example of IS response. Need your helps. Ohlbe 2020-05-26 17:46
- An example of IS response. Need your helps.Ohlbe 2020-05-26 14:42
- Placement of CC Helmut 2020-05-26 15:35
- An example of IS response. Shuanghe 2020-05-26 16:32
- An example of IS response. Ohlbe 2020-05-26 17:27
- Placement of CC Ohlbe 2020-05-26 17:32
- Placement of CC Helmut 2020-05-26 19:03
- Duplicate LLOQ and ULOQ Ohlbe 2020-05-26 19:43
- Duplicate LLOQ and ULOQ Helmut 2020-05-27 16:30
- Duplicate LLOQ and ULOQ Ohlbe 2020-05-26 19:43
- Placement of CC Helmut 2020-05-26 19:03
- An example of IS response. Shuanghe 2020-05-26 16:32
- Placement of CC Helmut 2020-05-26 15:35
- An example of IS response. Need your helps. ElMaestro 2020-05-26 15:44
- An example of IS response. Need your helps. ksreekanth 2020-07-06 13:37
- Trend analysis as per recent USFDA guideline dshah 2020-08-01 07:32
- Only for QCs; encouraged ≠ required Helmut 2020-08-01 14:13
- Only for QCs; encouraged ≠ required dshah 2020-08-03 09:17
- Deviation from the mean response Helmut 2020-08-07 13:28
- Only for QCs; encouraged ≠ required Shuanghe 2020-08-03 13:56
- Broken-stick regression Helmut 2020-08-04 18:04
- Only for QCs; encouraged ≠ required dshah 2020-08-03 09:17
- Only for QCs; encouraged ≠ required Helmut 2020-08-01 14:13
- An example of IS response. Need your helps. Sukalpa Biswas 2020-05-26 13:49
Ing. Helmut Schütz