Date: Thu, 15 Jul 1999 11:26:48 -0400
From: Raj <nagaraja@ufl.edu>
Subject: Blank data points
Hello,
I have a sparse data set of drug concentrations in patients (2-3 samples per patient). This includes blank plasma samples (time=0) also in about 50% of the population(total number of patients=120). I would like to know if all these blank sample data also should be included in the population analysis or it is valid to exclude them.
Thanks,
Raj
N.V. Nagaraja
Post Doc. Res. Assoc.
Dept of Pharmaceutics,
University of Florida,
Gainesville, FL-32610
Ph: (352) 375-6484
Fax: (352) 392-4447
Blank data points
Date: Mon, 19 Jul 1999 12:32:46 -0700
From: LSheiner <lewis@c255.ucsf.edu>
Subject: Re: Blank data points
If they are true blanks - that is, there is KNOWN to be no drug aboard, then they carry no PK information, and can (should) be discarded. Even in thiscase, however, they may carry useful information about the assay; i.e., the additive error at true zero.
LBS.
Lewis B Sheiner, MD Professor: Lab. Med., Biopharm. Sci., Med.
Box 0626 voice: 415 476 1965
UCSF, SF, CA fax: 415 476 2796
94143-0626 email: lewis@c255.ucsf.edu