1 Foundations of Laboratory Interpretation Free Online FlashCards

What does a laboratory reference interval describe?

A reference interval describes results expected in a defined reference population; it is not a diagnosis.

How does a clinical decision limit differ from a reference interval?

A clinical decision limit is a threshold used to guide a clinical decision; it is not simply a statistical reference interval.

What does a high or low laboratory flag establish?

A high or low flag prompts assessment; it does not establish a diagnosis by itself.

Why can an in-range result still matter over time?

A result can remain within the reference interval yet change substantially from the patient’s usual baseline.

Which specimen-handling steps can affect result reliability?

Follow test-specific instructions for preparation, collection container, fill volume, mixing, transport, storage, and processing.

Name patient-related factors that can contribute to laboratory result variation.

Age, pregnancy, recent food or drink, fasting status, medications, supplements, strenuous exercise, stress, and collection time can contribute to variation.

What should be prioritized when a result is unexpected?

Assess the patient and urgency first, then review specimen comments and collection conditions and follow policy for clarification or recollection. A suspected collection problem must not delay escalation of a concerning result or condition.

Why might a healthy person have a result outside the reference interval?

Many reference intervals cover the central 95% of a healthy reference group, so some healthy people fall outside them.

Which reference interval should you use to interpret a result?

Use the interval printed on the report because intervals can vary by laboratory, method, age, sex, pregnancy, and other characteristics.

What context helps interpret an out-of-range result?

Interpret a result alongside the patient’s symptoms, other results, how far it is outside the interval, and whether it is new or persistent.

How can a repeated or worsening change compare with an isolated abnormal result?

A small isolated out-of-range result may be less meaningful than a repeated or worsening change.

What supports a reliable comparison between laboratory results?

Compare results using the same units and, when possible, the same laboratory; also review collection times and relevant circumstances.