Module overview
Section 2 of 6 · Open sections

Required section · Section 2 of 6

Follow the analyte path

A drug is absorbed, distributed, metabolized, and eliminated, but the laboratory may measure the parent drug, a metabolite, or a conjugated form. Metabolites can be active or inactive, and some are formed by hydrolysis or conjugation. The analyte selected by the method determines what the result represents.

Hydrocodone can form norhydrocodone largely through CYP3A4 and hydromorphone partly through CYP2D6. Norhydrocodone is a more specific marker of hydrocodone ingestion than hydromorphone alone. CYP2D6 phenotype can change metabolite production, so a pattern requires method-aware interpretation.

Urine commonly detects metabolites, so parent-drug plasma half-life does not directly predict a urine window. Dose, repeated use, cutoff, metabolism, and renal function all affect whether an analyte is detected. A urine result is therefore a collection-time observation, not a clock.

Track the analyte path and the specimen path as separate but connected workflows. Confirm which form the method measures. Record collection and integrity facts before interpreting the analyte.

Illustrative drawing — this picture was drawn rather than captured.

Diagram shows hydrocodone branching to norhydrocodone through CYP3A4 and hydromorphone as a minor CYP2D6 product, then reaching a urine specimen.
Figure 1Hydrocodone can yield norhydrocodone and a small amount of hydromorphone before urinary excretion.

Use this sequence to keep collection, measurement, and interpretation distinct.

  1. Select the matrix

    Choose urine, oral fluid, blood, hair, or meconium for the actual question and program.

  2. Document integrity

    Apply written collection, labeling, storage, transport, and acceptability procedures.

  3. Measure the target

    Identify the method, calibrator, cutoff, and target analyte or drug class.

  4. State the boundary

    Report what the result supports without inferring dose, impairment, or exact time.

Knowledge checks

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Knowledge check 1

Which statements correctly describe the hydrocodone pathway? Select all that apply.

Choose at least 2 options.

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