Glossary
Abnormal flag
A marker such as H or L that shows a result falls above or below the reference range.
What is an abnormal flag on a lab result?
An abnormal flag is a short marker printed or shown next to a lab result when it falls outside the reference range. Flags help staff and clinicians spot the results that need a closer look without reading every value.
Common flags
- H: high, above the reference range.
- L: low, below the reference range.
- HH or LL: very high or very low, often used for critical values.
- A: abnormal, used for results that are not numbers, such as a positive result where negative is expected.
Exact codes vary between labs and systems. HL7 v2 messages carry the flag in its own field so it travels with the result from one system to another.
A flag does not mean something is wrong with the patient. Many flagged results are small, expected or explained by other factors. The ordering clinician decides what a flagged result means.
How Lab Desk handles it
Lab Desk's AI copilot highlights high and low values as soon as they are entered and lists flagged results for review first. Flags use an icon and a label, not color alone, and staff confirm every flag. The AI never diagnoses.
Related terms
- Reference range: The span of test values expected in a healthy reference population, used to judge whether a result is typical.
- Critical value: A result so far outside the expected range that it may signal an urgent risk and must be reported to a clinician right away.
- HL7: A family of standards for exchanging health information between systems, and the organization that publishes them.
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