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ratnakar1811 ★ India, 2011-04-07 15:39 (5560 d 21:13 ago) Posting: # 6869 Views: 2,894 |
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Dear All, Recently in one of the study, we have encountered a problem where the concentration could not be confirmed for one time-point, and the concentration is reported as value without confirmation in a situation where sample could not be repeated due to the unavailability of the plasma sample. Now the question is for PK and statistical analysis what concentration should be considered? Should we consider the concentration with no confirmation or reported as missing and perform the PK and statistical analysis or by both methods? Your valuable comments on this will be highly appreciated Thanking you in advance for reply. Best Regards, Ratnakar |
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Ohlbe ★★★ France, 2011-04-07 15:44 (5560 d 21:07 ago) @ ratnakar1811 Posting: # 6870 Views: 2,420 |
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Dear Ratnakar, What do you exactly mean by "the concentration could not be confirmed" ? Can you give some more details on what happened ? Regards Ohlbe — Regards Ohlbe |
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ratnakar1811 ★ India, 2011-04-08 08:25 (5560 d 04:26 ago) @ Ohlbe Posting: # 6872 Views: 2,339 |
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Dear Ohlbe, For the said sample the internal standard area response was significantly different from the mean of calibration and control samples. This sample was analysed seven times (one original and six reanalysis) but similar area response variation was observed. Since it is not confirmed whether the concentration value for said sample is accurate as the internal standard response has varied significantly, the value was reported as 'Concentration value with no confirmation available'. Is this information sufficient. Best Regards, Ratnakar |
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Dr_Dan ★★ Germany, 2011-04-08 11:10 (5560 d 01:41 ago) @ ratnakar1811 Posting: # 6873 Views: 2,336 |
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Dear Ratnakar I suggest to present in the text part of the report the results of the statistical evaluation of the study without the respective sample. In the appendix of the report you have to include a sensitivity analysis including an evaluation with the 'Concentration value with no confirmation available'. This sensitivity analysis showing that it is reasonable not to include the questionable concentration to the statistical evaluation should be referenced in the text part of the report. IMHO this is the correct way to present the results of your study. I hope this helps. Kind regards Dan — Kind regards and have a nice day Dr_Dan |
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paulhurleyuk ☆ NE UK, 2011-04-08 12:51 (5560 d 00:00 ago) @ ratnakar1811 Posting: # 6876 Views: 2,338 |
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Dear Ohlbe, ❝ For the said sample the internal standard area response was significantly different from the mean of calibration and control samples. So, like most things in this world, your response will depend on what you have previously said you will do. Do you have an SOP that describes criteria for Internal standard response? Was internal standard response tested and described in the BioA methopd validation? Does this sample meet those criteria? If it does, include it (possibly with a comment in the BioA report), if not, exclude it. There are several methods where the test system develops anti drug antibodies that can bind the analyte in biological fluid. These antibodies are often not able to differentiate a stable label internal standard which can produce this kind of variation, and renders the result unreliable. Paul. |
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