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Dear Simon,
Yes, this is always a problematic situation, and we could discuss it for hours. Treating the value at 8 hours as 0 will lead to an underestimation of the AUC. But treating it as missing will mean that you just ignore your experimental values when you don't like them. This can lead to heated discussions with regulators, which can be much less comfortable than posting on a forum.
If the next concentration is just above LLOQ, this can be due to analytical variability. But if it is much higher, I'd first try to understand what's happening: sample inversion, problem at the clinic, analytical error, anything. Even if it has no impact on this study, it can help prevent the recurrence of the problem.
IMHO it is a real pity that regulators are allergic to "PK repeats". Such repeats can help understand where the problem comes from, and they can avoid situations such as the one you describe.
Regards
Ohlbe
❝ Imagine his raw data stream looks like;
Yes, this is always a problematic situation, and we could discuss it for hours. Treating the value at 8 hours as 0 will lead to an underestimation of the AUC. But treating it as missing will mean that you just ignore your experimental values when you don't like them. This can lead to heated discussions with regulators, which can be much less comfortable than posting on a forum.
If the next concentration is just above LLOQ, this can be due to analytical variability. But if it is much higher, I'd first try to understand what's happening: sample inversion, problem at the clinic, analytical error, anything. Even if it has no impact on this study, it can help prevent the recurrence of the problem.
IMHO it is a real pity that regulators are allergic to "PK repeats". Such repeats can help understand where the problem comes from, and they can avoid situations such as the one you describe.
Regards
Ohlbe
—
Regards
Ohlbe
Regards
Ohlbe
Complete thread:
- BLQ values in Winnonlin Dr. Harish L. Rao 2009-09-10 07:53
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- BLQ values in Winnonlin Ohlbe 2009-09-11 00:18
- BLQ values in Winnonlin > Status codes tool SDavis 2009-09-11 08:13
- BLQ values in Winnonlin > Status codes toolOhlbe 2009-09-11 22:19
- Irregular profiles Helmut 2009-09-14 17:11
- About "PK repeats" Ohlbe 2009-09-14 22:01
- About "PK repeats" Helmut 2010-10-21 15:51
- About "PK repeats" Ohlbe 2010-10-21 16:38
- About "PK repeats" Helmut 2010-10-21 17:01
- About "PK repeats" Ohlbe 2010-10-21 17:32
- slowly going off-topic Helmut 2010-10-21 18:47
- About "PK repeats" Ohlbe 2010-10-21 17:32
- About "PK repeats" Helmut 2010-10-21 17:01
- About "PK repeats" ElMaestro 2010-10-21 16:56
- About "PK repeats" Helmut 2010-10-21 18:02
- About "PK repeats" Ohlbe 2010-10-21 16:38
- About "PK repeats" Helmut 2010-10-21 15:51
- BLQ Values in Winnonlin Dr. Harish L. Rao 2009-09-15 05:45
- About "PK repeats" Ohlbe 2009-09-14 22:01
- Irregular profiles Helmut 2009-09-14 17:11
- BLQ values in Winnonlin > Status codes toolOhlbe 2009-09-11 22:19
- BLQ values in Winnonlin > Status codes tool SDavis 2009-09-11 08:13
- BLQ values in Winnonlin Ohlbe 2009-09-11 00:18
Ing. Helmut Schütz