AGNP 2026 · First version for review
Dose-Related Reference Range Calculator
Enter the usual steady-state dose(s) and administration time(s), then select the sample collection date and time. The calculator uses one representative 24-hour steady-state cycle, from the earliest dose on the previous day to the same time today. To calculate a between-dose concentration after the earliest dose time, change the sampling date to the previous day (current date −1) and select the required time. Sampling after the end of the 24-hour cycle switches to an Expected concentration and assumes no further doses are given.
The DRR is a population expectation for the AGNP reference population, not a patient-specific therapeutic target.
Usual steady-state regimen
Select the drug, then enter each regular maintenance dose and administration time. Add a row for each daily dose time.
For missed, delayed, extra, or otherwise altered doses, use PK Viewer.
Calculation details
Method & references
AGNP 2026 main article and supplementary material
Each maintenance-dose row is modelled as a recurring 24-hour stream at steady state. Equation 4 and Equation 5 are evaluated for the source-defined parent or active-moiety components. Each active-moiety contributor retains its own PK parameters, and contributor and maintenance-row concentrations are summed.
AGNP defines the reference population as ideally age 18–65, nonsmoking, of normal body weight, and without pharmacokinetically relevant comorbidity, comedication, or genetic abnormalities in drug metabolism.
Lithium accepts lithium carbonate doses in mg, converts them internally to mmol lithium ion using the Li2CO3 molar mass, applies the AGNP molar calculation, and displays mmol/L.
Exact scheduled dose times are interpreted as pre-dose: the dose at that instant is not yet included, so the stream's elapsed time is 24 hours.
After the representative cycle ends, a derived geometric residual of the prior steady-state dose history assumes no subsequent doses and reports the mean expected concentration only. This extension is not an AGNP dose-related reference range.
Limitations: one-compartment linear pharmacokinetics with first-order absorption and elimination; source-defined parent or active-moiety components only; no patient covariates, Bayesian fitting, dose optimisation, therapeutic-range interpretation, or observed-value analysis.