Lab marker · Low

Low CYFRA 21-1 (lung cancer marker): what it means

A CYFRA 21-1 (lung cancer marker) result below the normal range is considered low. Here is what a reduced CYFRA 21-1 (lung cancer marker) can point to, and when it is worth discussing with a doctor.

Reference range: typically <~3.3 ng/mL; a monitoring marker for non-small-cell lung cancer — used to follow known disease and treatment response, not to screen

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What a low CYFRA 21-1 (lung cancer marker) can mean

  • Normal or low — the expected result, and reassuring during monitoring.
  • A falling level during treatment — suggests the therapy is working.
  • Not a rule-out — a normal CYFRA 21-1 does not exclude lung cancer.

When to discuss with a doctor

CYFRA 21-1 is a specialist monitoring marker for non-small-cell lung cancer, not a screening or stand-alone diagnostic test. In someone with known lung cancer it is followed over time — a falling trend is reassuring, a rising trend prompts imaging and reassessment. Outside that setting a mildly raised value is often non-specific, from benign lung disease or reduced kidney function, and a normal value never rules cancer out. It is usually read together with other lung markers because different tumour types raise different ones. Mediora.AI can surface a CYFRA 21-1 trend and show it alongside related markers, but this needs specialist assessment — the interpretation belongs with your oncology team.

Conditions this can relate to

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Mediora.AI is informational - interpretation, not a diagnosis. A single out-of-range value is common and often benign; always discuss decisions with your doctor.