Required section · Section 5 of 6

Choose the bounded laboratory action

A reported concentration becomes discordant when its timing, source, or method does not support its intended use. First verify dose, route, exact last-dose time, draw time, and specimen source. A same-line draw from an active or recently used infusion lumen is a plausible preanalytical explanation for an unexpected high level.

If a peripheral draw or unused lumen is not available, follow the written same-line protocol for stopping infusion, flushing, discard volume, and documentation. Do not invent a flush interval or acceptability rule at the bench. Recollection and an explanatory comment are bounded laboratory actions when the evidence does not support interpretation.

For abnormal phenytoin binding, a direct free level is preferred over assuming a total result reflects active drug. For a local critical value, immediate communication and documented read-back follow the laboratory procedure, while the numeric threshold remains locally approved. These actions protect the patient without directing therapy.

Choose release, recollection, comment, or critical notification from verified evidence and local policy.

Ordering exercise

Place the laboratory actions in the order that establishes whether a discordant TDM concentration can be interpreted.

1. Choose bounded action

Release with context, recollect/comment, or use local critical notification procedure.
2. Assess method context

Identify assay method, relevant interference, and comparability with prior results.
3. Verify collection history

Confirm dose, route, last-dose or infusion-end time, draw time, and source.

Knowledge checks

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Knowledge check 1

An unexpectedly high drug level was drawn from the same lumen used for infusion, with no documented local same-line protocol. What is the bounded laboratory action?

Choose one option.

Seek a peripheral or unused-lumen recollection and document or comment the limitation under local policy.

Release it as definitive and recommend reducing the dose.

Apply an assumed flush and discard volume.

Knowledge check 2

Select actions required when a TDM result meets the locally approved critical list.

Choose at least 2 options.

Immediately notify the ordering entity and responsible user.

Document the notification and read-back or confirmed electronic receipt.

Use one national numeric threshold for every laboratory.

Section status

Finish this section

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The module finishes after every required section is marked done and every check in those sections is correct.