zero (0), missing (NA), or BLLOQ (0 or NA) in bear [🇷 for BE/BA]

posted by yjlee168 Homepage – Kaohsiung, Taiwan, 2016-02-03 10:04 (2976 d 22:20 ago) – Posting: # 15922
Views: 24,070

Dear mittyri and others,

I guess the issue (zero, BLLOQ or missing) may not be solved quickly. Thus I leave the decision to users if it is a real zero conc. (0) or a missing (NA), or a BLLOQ (0 or NA). Basically, the drug plasma conc. should be input as either a zero or a NA in bear. If it is a NA, it will be ignored (or deleted). If it is a zero conc., it will be treated as a number in AUC/AUMC calculation. However, since a zero conc. cannot be used to estimate λz, any zero conc. will not be counted as a valid data point. Like the following example:

-> the subj# 1 (Ref.) in sequence# 2, period# 2,
    λz (kel) cannot be calculated with ARS or AIC.
 subj seq prd drug  time conc
    1   2   2    1  0.00    0
    1   2   2    1  0.25    0
    1   2   2    1  0.50  125
    1   2   2    1  0.75    0
    1   2   2    1  1.00  932
    1   2   2    1  1.50 1343
    1   2   2    1  2.00 1739
    1   2   2    1  3.00 1604
    1   2   2    1  4.00    0
    1   2   2    1  8.00  797
    1   2   2    1 12.00    0
    1   2   2    1 24.00    0

❝ I think you are close enough to pre-processing of datasets (as in PHX - BQL rules, I can send you PDF guide if needed, there are some examples of rules), so the users can define their own rules of data handling (missing, BLOQ depending on position of data).


All the best,
-- Yung-jin Lee
bear v2.9.1:- created by Hsin-ya Lee & Yung-jin Lee
Kaohsiung, Taiwan https://www.pkpd168.com/bear
Download link (updated) -> here

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