Time allowance windows? [Study Per­for­mance]

posted by Helmut Homepage – Vienna, Austria, 2015-08-11 02:44 (3152 d 15:42 ago) – Posting: # 15217
Views: 8,616

Hi Joy,

❝ how to justify acceptable deviation of blood sampling time in BE studies ?


I’m not sure what you mean by justification here. There are many possible reasons which could justify a deviation: Technical problems (blocked venflow, difficulties in repeated venipuncure), logistics (subject arrives late for ambulatory blood draw), whatsoever.
Or do you mean the “magic” time allowance window (TAW)? Most CROs state in the protocol & CRF that sampling within the TAW must not be commented in the CRF. TAWs depend on the sampling schedule (increasingly wide). Example according to Papst* with an “irrelevant” deviation of 5% below:

scheduled ∆1    ∆2     TAW
  (h)     (h)   (h)    (min)
 pd                    –30
         0.25
 0.25            0.25   +1
         0.25
 0.5             0.25   +1
         0.25
 0.75            0.25   +1
         0.25
 1               0.25   +1
         0.25
 1.25            0.25   +1
         0.25
 1.5             0.25   +1
         0.25
 1.75            0.25   +1
         0.25
 2               0.25   +1
         0.25
 2.25            0.25   +1
         0.25
 2.5             0.25   +1
         0.5
 3               0.5    +2
         0.5
 3.5             0.5    +2
         0.5
 4               0.5    +2
         1
 5               1      +3
         1
 6               1      +3
         2
 8               2      +6
         2
10               2      +6
         2
12               2      +6
         4
16               4     +12
         8
24                     +12


∆1 is the difference between sampling time points. ∆2 is the smallest of two neighbouring ∆1s.
However, rarely I see only positive TAWs in CRFs. Most CROs state ±sumfink. I don’t get it & concur with Papst, who wrote:

Any sampling occuring too early is a deviation that should be reported even if pharmacokinetically irrelevant, since there are only a few plausible reasons why an activity should have been performed earlier than planned.




Dif-tor heh smusma 🖖🏼 Довге життя Україна! [image]
Helmut Schütz
[image]

The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes

Complete thread:

UA Flag
Activity
 Admin contact
22,957 posts in 4,819 threads, 1,638 registered users;
92 visitors (0 registered, 92 guests [including 11 identified bots]).
Forum time: 17:26 CET (Europe/Vienna)

Nothing shows a lack of mathematical education more
than an overly precise calculation.    Carl Friedrich Gauß

The Bioequivalence and Bioavailability Forum is hosted by
BEBAC Ing. Helmut Schütz
HTML5