How to prepare
No fasting is required. Eat and drink normally beforehand.
Timing is the most important factor for this test. For a 28-day cycle, collection on day 21 captures the expected mid-luteal peak. If your cycle is shorter or longer than 28 days, collection should be approximately 7 days after you expect ovulation to have occurred. If you use ovulation predictor kits, this test is ideally done 7 days after a positive result.
Testing at the wrong time in your cycle will produce a misleading result. If you are unsure when to test, ask your practitioner before booking. A healthcare professional will take a blood sample from a vein in your arm.
After the test
Share your results with your GP, gynaecologist, or fertility specialist. If mid-luteal progesterone is low on a correctly timed sample, your practitioner will discuss whether further investigation is appropriate — this may include repeat testing, additional hormone markers, or a referral to a reproductive specialist.
Do not adjust medications or supplement with progesterone based on this result alone without consulting your practitioner.
Your test results will be available in your private dashboard. If there are any urgent issues, we'll let you know so you can follow up with your health professional.
Understanding results
Results are reported in nanomoles per litre (nmol/L). Reference ranges are cycle-phase specific. A mid-luteal progesterone above approximately 25–30 nmol/L is generally taken as evidence of ovulation, though reference ranges vary between laboratories.
A result below this threshold on a correctly timed sample may indicate that ovulation did not occur, or that the luteal phase is inadequate. Low progesterone in early pregnancy may also be of concern to your practitioner and may prompt further monitoring.
Because progesterone levels fluctuate over the course of the day, a borderline result may sometimes be repeated. Your practitioner will interpret the number in the context of your cycle length, timing, and clinical picture.