4-Hydroxyestrone, Urine Creatinine Ratio Unit Converter

4-Hydroxyestrone (4-OH-E1) is a metabolite of estrone, one of the body's main estrogens. It belongs to a group called catechol estrogens, which are formed when estrone is hydroxylated (has an oxygen-hydrogen group added) at the 4-position on its chemical ring.

This marker measures 4-OH-E1 levels in urine, corrected for urine creatinine concentration. The creatinine correction accounts for how dilute or concentrated the urine sample is, providing a more reliable measurement.

4-OH-E1 is typically present in small amounts compared to other estrogen metabolites like 2-hydroxyestrone. Unlike 2-hydroxyestrone, which has minimal estrogenic activity, 4-hydroxyestrone retains significant estrogenic potency.

4-Hydroxyestrone is produced primarily in the liver, and to a lesser extent in other tissues, when estrone is hydroxylated by cytochrome P450 enzymes (mainly CYP1B1 and CYP1A1).