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Fragment of cytokeratin 19 in the blood
Last reviewed: 23.04.2024
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The reference values (norm) of the concentration of the fragment of cytokeratin 19 (CYFRA-21-1) in serum - up to 3.3 ng / ml.
Cytokeratins are insoluble skeletal proteins. Unlike cytokeratins, fragments of cytokeratin are soluble in serum. Cytokeratins play an important role in tissue differentiation. CYFRA-21-1 has good specificity for benign lung diseases, the 3.3 ng / ml separation point provides a specificity of 95%. A slight rise in CYFRA-21-1 to 10 ng / ml is detected with progressive benign liver diseases and especially with kidney failure.
CYFRA-21-1 is a marker of non-small cell carcinoma of the lung. With a specificity of 95%, CYFRA-21-1 has a significantly higher sensitivity (49%) than CEA (29%). The sensitivity of CYFRA-21-1 in squamous cell carcinoma of the lungs is much higher (60%) than the sensitivity of CEA (18%). CYFRA-21-1 and CEA show a similar diagnostic sensitivity (42% and 40%, respectively) for pulmonary adenocarcinoma. The combination of these two markers increases the sensitivity to 55%.
CYFRA-21-1 is the most informative of all known markers for monitoring muscular-invasive bladder carcinoma. With a specificity of 95%, CYFRA-21-1 has a sensitivity of 56% for invasive tumors of all stages. The sensitivity of CYFRA-21-1 depends on the stage of the disease: 4% at stage I, more than 33% at stage II, 36% at III, and 73% at stage IV of bladder cancer.
More than 50% of bladder tumors do not infiltrate the muscle layer. They are easily detected by urological examination. It is more difficult to diagnose invasive tumors. Monitoring of CYFRA-21-1 markers in many cases allows revealing such forms of bladder carcinoma.
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