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Description

Pharmacokinetics Concentrations (PC) is a Findings domain used for the concentrations of analyte or metabolites in biological fluids (e.g. blood, urine, saliva, breast milk ) or tissues as a function of time. The measuring of nicotine blood concentrations after a subject is exposed to a tobacco product is often performed. Information about sampling for pharmacokinetic (PK) concentration is collected on CRFs with the goal to reconcile or link sampling information (e.g., collection timing, specimen volumes) with PK concentration results provided by the laboratory. Tabulation PC records are compiled when joining CRF sampling information and PK concentration results. This is similar to scenario 1 in Section 2.7.6.9,  CDASH Laboratory Test Results (LB).

The goals of the PC domain are:

• To standardize specimen collection details in the CRF for PK samples collected at fixed time points or over timed intervals
• To provide examples as to the collection of data that is closely related to PK sampling (e.g., subject's most recent exposure to product, exposure record considered to be the reference for timed PK samples)
• To document the data flow from the CRF to the tabulation PC dataset

The CDASHIG PC domain defines fields for:

1. The date and time of PK sample collections for the scenarios listed below. Note that the sampling approach may depend on how the body metabolizes and clears the analyte.
   1. Fixed defined time points (e.g., 4 HRS POSTDOSE)
   2. Across a collection interval (e.g., 2-4 HRS POSTDOSE)
2. Specimen properties (e.g., pH, specimen volume)

Note that specimens collected to measure study product (usually nicotine) concentration at an instant in time are generally associated with specimen types such as plasma, serum, or whole blood. Specimens collected over a timed interval are generally associated with specimen types such as urine or feces.

In the case of fixed time points, the date (PCDAT) and time (PCTIM) of collection for each sample is recorded on the CRF. The protocol defines the time points at which samples are to be collected in relation to an intervention such as exposure to product. This "reference" is depicted in Figure 1 by the longer vertical line and would correspond to a date and time in the Exposure as Collected (EC) or Exposure (EX) domain.

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PK Sample Collection Over a Time Interval

Similarly, for PK specimens collected to measure excretion over a time interval, PCDAT and PCTIM capture the start date and time of the interval collection. End date (PCENDAT) and end time (PCENTIM) capture the end of the timed interval collection. As with fixed-time point collections, these timed intervals are performed in relation to an intervention such as exposure to product. This "reference" is depicted in Figure 2 by the longer vertical line and would correspond to a date and time in the EC or EX domain.

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Specification

Assumptions