Specimen requirement

Adult patient:

  Clotted blood tube (Serum gel separator clot activator tube)

Minimum blood volume: 5 mL

Paediatric patient:

Paediatric clotted blood tube

Number of vials: 2

Minimum blood volume: 1.6 mL

Authorisation code required

No

24 Hr available service

No

Method

Immunoassay

Reference interval

(Source: from manufacturer's kit inserts Prog II and Prog III (for Pregnancy))

Clinical indication

Investigation of infertility

Result interpretation

Progesterone, in conjunction with estrogens, regulates reproductive tract functions during the menstrual cycle. Progesterone is critical in preparing the endometrium for blastocyst implantation and the maintenance of pregnancy.

The major sources of progesterone are the corpus luteum and the placenta in women. Minor sources of progesterone are the adrenal cortex in men and women, and the testes in men.

Progesterone levels are low during the follicular phase of the menstrual cycle. After ovulation, progesterone production by the corpus luteum increases rapidly, reaching a maximum concentration 4 to 7 days after ovulation. These levels are maintained for 4 to 6 days then fall to baseline levels, inducing menstruations. During pregnancy, progesterone levels rise steadily to their highest levels in the third trimester.

Clinical evaluation of progesterone confirms ovulation and normal luteal function in nonpregnant women. Inadequate progesterone production by the corpus luteum may indicate luteal phase deficiency (LPD), which is associated with infertility and early miscarriage.

Women using oral contraceptives have suppressed progesterone levels.

Measurement of uncertainty

See table.

Frequency of measurement

Daily