CYFRA 21-1
Cytokeratin fragment 21-1, a tumor marker primarily used for monitoring non-small cell lung cancer and other epithelial tumors.
Category: Tumor Markers
Also known as: cyfra 21 - 1
Reference range: 0–3.3 ng/mL (Source: ABIM)
Standard unit: ng/mL
High values may indicate
Elevated levels may indicate presence of epithelial tumors, particularly non-small cell lung cancer, or disease progression.
Low values may indicate
Normal levels. No clinical concern.
Frequently asked questions
- What is a normal CYFRA 21-1 level?
- A typical reference range for CYFRA 21-1 is 0–3.3 ng/mL (source: ABIM). Reference ranges vary by laboratory, age, and sex, so always compare against the range on your own lab report.
- What units is CYFRA 21-1 measured in?
- CYFRA 21-1 is most commonly reported in ng/mL. Labs in different countries may use other units — you can convert between them with BloodId's blood test unit converter.
- Where do CYFRA 21-1 reference ranges come from?
- BloodId uses ABIM standard reference ranges and educational information from MedlinePlus (see our methodology). Reference ranges still vary by lab, age, and sex, so always compare against your own report.
- Can I track CYFRA 21-1 over time?
- Yes. Upload results from any lab and BloodId charts your CYFRA 21-1 over time against its reference range, so you can see whether the trend is rising, falling, or stable.
Related biomarkers
Source: BloodId admin-reviewed
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