## BQL = 0: bad rule [Software]

Hi Babe_Ruth,

» » Bad practice to force BQLs after tmax to zero

»

» What about for sparse sampling methods?

Sparse sampling is another cup of tea. Sounds trivial but actually isn’t.

» If there are 3 samples/time point, wouldn't we want to use 3 values for the calculation of the mean concentration? In which case imputing BQL concentrations with a value of 0 or close to 0 would be more favorable than not including the value altogether?

Some ideas:

» […] I'm interested in learning more about what I'm doing.

Basic research is what I’m doing

when I don’t know what I’m doing.

» Browsing these forums in my spare time really helps me see where others are in environment of the Ba/Be world :) Searching old topics have answered most of the questions I have had, which is super helpful.

Maybe you can convince your employer to browse the forum in your payed time…

» » Bad practice to force BQLs after tmax to zero

»

» What about for sparse sampling methods?

Sparse sampling is another cup of tea. Sounds trivial but actually isn’t.

» If there are 3 samples/time point, wouldn't we want to use 3 values for the calculation of the mean concentration? In which case imputing BQL concentrations with a value of 0 or close to 0 would be more favorable than not including the value altogether?

Some ideas:

- Phoenix/WinNonlin supports only the linear trapezoidal rule for spare sampling. Hence, anything is possible.

- Imputing 0 for post dose BQLs goes against the grain for me. Most commonly used is LLOQ/2. But why the heck divide by two? What I would do: Try to get an idea of the PK (well, difficult in the first TK-study of a drug). Perform simulations and based on the LLOQ & sampling schedule come up with a reasonable ratio.

- Try also the
**R**-package`PK`

* which contains more methods for sparse sampling designs than PHX/WNL.

Both authors are members of the forum. I’ll notify them; maybe they can jump into the discussion.

» […] I'm interested in learning more about what I'm doing.

Basic research is what I’m doing

when I don’t know what I’m doing.

*Wernher von Braun*» Browsing these forums in my spare time really helps me see where others are in environment of the Ba/Be world :) Searching old topics have answered most of the questions I have had, which is super helpful.

Maybe you can convince your employer to browse the forum in your payed time…

- Jaki T, Wolfsegger MJ.
*Estimation of pharmacokinetic parameters with the R package PK.*Pharm Stat. 2011;10(3):284–8. doi:10.1002/pst.449.

—

Helmut Schütz

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

Science Quotes

*Dif-tor heh smusma*🖖Helmut Schütz

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

Science Quotes

### Complete thread:

- WNL Calculation of partial areas > tlast with BQL= 0 rule Babe_Ruth 2018-07-13 21:36 [Software]
- WNL Calculation of partial areas > tlast with BQL= 0 rule ElMaestro 2018-07-13 22:25
- BQL = 0: bad rule Helmut 2018-07-13 23:28
- BQL = 0: bad rule Babe_Ruth 2018-07-16 15:02
- BQL = 0: bad ruleHelmut 2018-07-16 16:02
- BQL = 0: bad rule martin 2018-07-16 20:03

- BQL = 0: bad ruleHelmut 2018-07-16 16:02
- BQL = 0: bad rule martin 2018-07-16 20:43

- BQL = 0: bad rule Babe_Ruth 2018-07-16 15:02
- is zero positive? mittyri 2018-07-13 23:31
- sgn(0) = 0 Helmut 2018-07-13 23:58
- is zero positive? Babe_Ruth 2018-07-16 14:49