CYFRA 21-1 is a biomarker measured in blood tests. It provides information about cellular activity. This marker helps medical professionals gain insights into a patient’s condition. Its presence and levels can offer valuable clues, guiding further diagnostic or monitoring steps.
Understanding CYFRA 21-1
CYFRA 21-1 is a soluble fragment of cytokeratin 19 (CK19), a protein found in epithelial cells. Epithelial cells line organs and structures like the lungs, bladder, and digestive tract. When these cells undergo damage, rapid turnover, or specific disease processes, fragments of CK19 can be released into the bloodstream.
The presence of CYFRA 21-1 in the blood indicates cellular disruption or increased activity in epithelial tissues. While CK19 is rarely detected in the blood of healthy individuals, its elevated presence can signal underlying medical conditions. This makes CYFRA 21-1 a useful indicator for monitoring changes in cellular health.
Primary Uses of CYFRA 21-1 Testing
CYFRA 21-1 testing is primarily used in the management of non-small cell lung cancer (NSCLC), for monitoring treatment response and detecting recurrence. It is considered a sensitive and specific marker for NSCLC, especially for the squamous cell subtype. Elevated levels are frequently observed in patients with squamous NSCLC, with about 59.8% of cases showing increased levels compared to 42.2% in non-squamous NSCLC.
The marker also holds prognostic value in NSCLC, where higher levels often correlate with a poorer prognosis, even in non-squamous types. It helps clinicians assess therapy effectiveness by observing changes in its levels over time. Beyond lung cancer, CYFRA 21-1 has been explored as a potential biomarker in other cancers, including biliary tract, pancreatic, breast, and urothelial carcinoma, though its role in these is less established.
Interpreting Test Results
Interpreting CYFRA 21-1 test results involves understanding what different levels might signify, though normal ranges can vary slightly between laboratories. Generally, a reference range for healthy individuals might be below 3.3 ng/mL or 1.96 ng/mL, but specific cut-off values can differ. Elevated levels suggest increased cellular activity or damage, often associated with the conditions for which the test is performed. For instance, in pancreatic cancer, a level above 1.96 ng/mL has shown high sensitivity and specificity for diagnosis.
CYFRA 21-1 is not a standalone diagnostic test. A single elevated reading does not confirm a diagnosis of cancer or any other specific condition. Instead, results must always be interpreted in conjunction with a comprehensive medical evaluation, which includes other clinical findings, imaging studies like CT scans or MRIs, and biopsy results. Observing trends in CYFRA 21-1 levels over time, such as persistently rising or falling values, can provide more meaningful information about disease progression or response to treatment than a single measurement.
Factors Influencing CYFRA 21-1 Levels
Several non-cancerous conditions and physiological factors can elevate CYFRA 21-1 levels, requiring a thorough medical assessment. Benign lung diseases, such as pneumonia, tuberculosis, or chronic obstructive pulmonary disease (COPD), can cause increases in CYFRA 21-1 due to inflammation or cellular turnover in the lung tissue. Liver conditions, including cirrhosis or hepatitis, and kidney failure may also impact CYFRA 21-1 levels because these organs play a role in clearing substances from the blood.
Inflammatory processes throughout the body can sometimes cause a mild elevation. Because of these potential confounding factors, an elevated CYFRA 21-1 level alone is insufficient for diagnosis and necessitates further investigation. A comprehensive medical evaluation helps differentiate between cancer-related elevations and those caused by other benign or inflammatory conditions.