Serum or Plasma Substance Concentration (Immunoassay) for Progesterone

When Is This Test Done?

Your doctor may order this test to check for ovulation, diagnose fertility issues, evaluate hormonal imbalances, or monitor conditions like polycystic ovary syndrome (PCOS) or pregnancy. It can also be used during pregnancy to track early development or rule out complications.

What Does the Test Involve?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it is analyzed using an immunoassay method to measure progesterone concentration. Results are reported in arbitrary units per liter (U/L) or mass concentration equivalents.

What Are Common Reasons for Testing?

Common reasons include assessing fertility, diagnosing menstrual cycle irregularities, evaluating symptoms of hormonal disorders, or monitoring reproductive health before or during pregnancy. It may also be used in research or clinical trials involving hormone regulation.

What Might Affect Results?

Several factors can influence progesterone levels, including the timing of the blood draw (e.g., mid-luteal phase for fertility evaluation), medications (like birth control), stress, illness, or recent physical activity. Smoking or certain medications (e.g., steroids) can also alter results.