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CA 125 Unit Converter
Cancer Antigen 125 (CA 125) is a high molecular weight mucin-like glycoprotein expressed by coelomic epithelium during fetal development. In adults, it can be elevated in both benign and malignant conditions affecting the mesothelial cells of the pleura, pericardium, and peritoneum.
Clinically, CA 125 is the primary tumor marker for Epithelial Ovarian Cancer. It is used to monitor response to chemotherapy, detect recurrence, and aid in the evaluation of pelvic masses (often in conjunction with HE4 in the ROMA algorithm). However, it lacks specificity for screening the general population, as it can be raised in endometriosis, liver cirrhosis, and heart failure. Results are reported in Units per milliliter (U/mL) or kU/L. This converter allows seamless switching between these reporting standards.
SI Units
RecommendedUnits per milliliter (Standard Clinical Unit).
Conventional Units
Clinical Context
Reference Range: In healthy women, CA 125 is typically < 35 U/mL.
Levels can be physiologically elevated during menstruation and the first trimester of pregnancy. In postmenopausal women with an adnexal mass, a level > 35 U/mL has a high positive predictive value for malignancy. For monitoring treatment, a 50% decrease is often considered a partial response. The conversion factor is 1:1 for most standard units: 1 U/mL = 1 kU/L = 1 IU/mL.
Clinical References
How to Use This Calculator
Follow these steps to get accurate clinical conversions instantly.
Enter Values
Input your laboratory results into the corresponding unit field (e.g., U/mL). You can use either dot or comma decimals.
Automatic Conversion
The calculator works in real-time. As you type in one field, all other units (like kU/L) are instantly updated.
Verify Units
Check the SI Units section. Note that U/mL and kU/L are numerically identical.
Reset
Use the Clear button to reset all fields before starting a new calculation.
Frequently Asked Questions & Tips
CA 125 is defined by its antibody binding reactivity, not by weight. There is no standard conversion to mass.
Yes, for CA 125, “Units” and “International Units” are used interchangeably.