Mark I disagree (more than a little). If a sample is reported as BQL and the expected value is 0 (i.e., pre-dose, not endogenous), what information is there about assay precision. If the error model is additive (or additive + proportional), the sample will contribute zero to the objective function. If the error model is proportional, NONMEM will report an error (0/0). I agree that pre-dose samples > LOQ provide IMPORTANT information about assay precision.
Were you evacuated during the fires? Dennis Dennis Fisher MD P < (The "P Less Than" Company) Phone / Fax: 1-866-PLessThan (1-866-753-7784) www.PLessThan.com <http://www.plessthan.com/> > On Nov 6, 2019, at 8:40 AM, Mark Sale <ms...@nuventra.com> wrote: > > Dennis, > I may have to disagree, a little. There is information, a little, in a pre > dose BQL, about assay precision. I think you might agree that is a pre dose > sample is NOT BQL (which happens), tells you (and NONMEM) something about the > assay. Converse, even a BQL predose sample has a small amount of information. > That not withstanding, we also remove and pre-dose BQLs from the data set. > > > Mark Sale M.D. > Senior Vice President, Pharmacometrics > Nuventra Inc. > 2525 Meridian Parkway, Suite 200 > Durham, NC 27713 > Phone (919)-973-0383 > ms...@nuventra.com <x-msg://138/ms...@kinetigen.com> > > > CONFIDENTIALITY NOTICE The information in this transmittal (including > attachments, if any) may be privileged and confidential and is intended only > for the recipient(s) listed above. Any review, use, disclosure, distribution > or copying of this transmittal, in any form, is prohibited except by or on > behalf of the intended recipient(s). If you have received this transmittal in > error, please notify me immediately by reply email and destroy all copies of > the transmittal. > > From: owner-nmus...@globomaxnm.com <mailto:owner-nmus...@globomaxnm.com> > <owner-nmus...@globomaxnm.com <mailto:owner-nmus...@globomaxnm.com>> on > behalf of Dennis Fisher <fis...@plessthan.com <mailto:fis...@plessthan.com>> > Sent: Wednesday, November 6, 2019 7:23 AM > To: nmusers@globomaxnm.com <mailto:nmusers@globomaxnm.com> > <nmusers@globomaxnm.com <mailto:nmusers@globomaxnm.com>>; Bill Denney > <wden...@humanpredictions.com <mailto:wden...@humanpredictions.com>> > Cc: Carlos ST <carlos.serr...@gmail.com <mailto:carlos.serr...@gmail.com>>; > Steven Shafer <steven.sha...@stanford.edu <mailto:steven.sha...@stanford.edu>> > Subject: Re: [NMusers] Using evid 0 before dosing > > WARNING: This email originated from outside of the company. Do not click > links or open attachments unless you recognize the sender and are expecting > the message. > Bill > > I think that the issue is more complicated than you acknowledge. > > Assuming that the drug is not an endogenous substance, the pre-dose > concentration is likely to be BQL. However, there are two kinds of BQL > values: > 1. Samples that are truly zero because they were obtained pre-dose > 2. Samples that are > 0 but < LOQ. > Yet both are reported as BQL. > > From my perspective, a BQL value pre-dose provides no information to NONMEM. > Therefore, one should apply EVID=2 to that sample. This allows a prediction > at that timepoint but the sample does not influence the analysis. > > Dennis > > Dennis Fisher MD > P < (The "P Less Than" Company) > Phone / Fax: 1-866-PLessThan (1-866-753-7784) > www.PLessThan.com <http://www.plessthan.com/> > > > > >> On Nov 6, 2019, at 7:12 AM, Bill Denney <wden...@humanpredictions.com >> <mailto:wden...@humanpredictions.com>> wrote: >> >> Hi Carlos, >> >> It is commonly used. For most datasets, there will be at least one >> observation that occurs before dosing to estimate the baseline value, and in >> almost every scenario, the modeling dataset should mirror the real world >> actions. So, there is no issue with it, and usually you will have an EVID=0 >> before the first dose. >> >> Thanks, >> >> Bill >> >> -----Original Message----- >> From: owner-nmus...@globomaxnm.com <mailto:owner-nmus...@globomaxnm.com> >> <owner-nmus...@globomaxnm.com <mailto:owner-nmus...@globomaxnm.com>> On >> Behalf >> Of Carlos ST >> Sent: Wednesday, November 6, 2019 10:03 AM >> To: nmusers@globomaxnm.com <mailto:nmusers@globomaxnm.com> >> Subject: [NMusers] Using evid 0 before dosing >> >> Dear NMUsers, >> >> I would like advice in the best practice to use evid 0 before dosing, which >> is to say an observation just before a dosing (*to estimate the value in >> that compartment just before dosing event). >> >> Thank you, >> >> Carlos,
