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Dr. Harish L. Rao ☆ India, 2009-01-16 10:35 (5956 d 04:29 ago) Posting: # 3043 Views: 5,582 |
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Dear Group Members, First of all, wish you all "A VERY HAPPY & PROSPEROUS NEW YEAR 2009". During WinNonlin data analysis, do we need to include zero values? Eg: If the concentration at 12 hours is below the limit of quantification (BLOQ), do we need to include this timepoint as 12, BLOQ or 12, 0 for WinNonlin data analysis? If we have measured the concentration prior to dosing & found the concentration to be BLOQ, do we need to include this timepoint as 0, BLOQ or 0, 0? Does WinNonlin treat 12, BLOQ same as 12, 0? Thanks & regards, Dr. Harish L. Rao |
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Helmut ★★★   Vienna, Austria, 2009-01-17 01:18 (5955 d 13:46 ago) @ Dr. Harish L. Rao Posting: # 3054 Views: 5,193 |
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Dear Harish!, ❝ During WinNonlin data analysis, do we need to include zero values? Eg: If the concentration at 12 hours is below the limit of quantification (BLOQ), do we need to include this timepoint as 12, BLOQ or 12, 0 for WinNonlin data analysis? Please provide more informations! Is 12 hours the last sampling time and if not, were there following concentrations above the LLOQ? ❝ If we have measured the concentration prior to dosing & found the concentration to be BLOQ, do we need to include this timepoint as 0, BLOQ or 0, 0? Most people would set this value to zero. ❝ Does WinNonlin treat 12, BLOQ same as 12, 0? No. If you have a text-value (like 'BQL') in your worksheet, the value is treated as 'Missing'. Generally it's advisable to define a procedure in an SOP, which can be implemented in WinNonlin by means of the 'Status Code Transformation Wizzard' (Tools > Status Codes (i.e. BQL)...). For details see the 'WinNonlin User' Guide' p 69-74 (for v5.2.1). — Dif-tor heh smusma 🖖🏼 Довге життя Україна! ![[image]](https://static.bebac.at/pics/Blue_and_yellow_ribbon_UA.png) Helmut Schütz ![[image]](https://static.bebac.at/img/CC by.png) The quality of responses received is directly proportional to the quality of the question asked. 🚮 Science Quotes |
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Dr. Harish L. Rao ☆ India, 2009-01-17 04:07 (5955 d 10:57 ago) @ Helmut Posting: # 3055 Views: 4,600 |
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Dear Helmut, Thanks for your reply. In my example, 12 hours is not the last sampling timepoint. The following concentrations were above LOQ. In such cases, do we need to mention this timepoint as 12,BLOQ or 12,0 in WinNonlin? Since 12,BLOQ and 12,0 are treated differently by WinNonlin, which one of these would be the right way of data handling in WinNonlin? Alternately, is it right to totally skip this timepoint entry in WinNonlin? Thanks & regards, Dr. Harish L. Rao |
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Helmut ★★★ Vienna, Austria, 2009-01-18 16:13 (5953 d 22:51 ago) @ Dr. Harish L. Rao Posting: # 3057 Views: 4,832 |
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Dear Harish! ❝ In my example, 12 hours is not the last sampling timepoint. The following concentrations were above LOQ. In such cases, do we need to mention this timepoint as 12,BLOQ or 12,0 in WinNonlin? First of all I would suggest to perfom a blinded plausibility review of analytical data. You must have an SOP in place which describes when and why a value may be requested for reanalysis based on PK grounds. Only if the value was confirmed as BQL, I (!) would keep it as 12,BQL and set WinNonlin's options to deal with Missing values accordingly: Tools > Options... > Models > Default Parameter Options (NCA calculation method) > Linear Trapezoidal (Linear/Log Interpolation) ❝ Since 12,BLOQ and 12,0 are treated differently by WinNonlin, which one of these would be the right way of data handling in WinNonlin? After dosing we know only one thing for sure: the concentration is not zero! OK, to stay with this example of a dose of 10 mg of a drug with a molecular mass of 200 g/mol and a half life of 2 hours on the average only 1 molecule is left in the systemic circulation after 129 hours...  ❝ Alternately, is it right to totally skip this timepoint entry in WinNonlin? IMHO no - you do have a result: BQL. See also these two related earliers threads initiated by Ratnakar and DLabes: some collegues have other opinions! — Dif-tor heh smusma 🖖🏼 Довге життя Україна! Helmut Schütz The quality of responses received is directly proportional to the quality of the question asked. 🚮 Science Quotes |
Ing. Helmut Schütz