a. Tests are based on the presence of human chorionic gonadotropin (HCG) in the urine or blood.

(1) Urine. This test can be performed accurately 42 days after the last menstrual period or 2 weeks after the first missed period. The first urine specimen of the morning is the best one to use.

(2) Blood. Radioimmunoassays (RIA) can detect HCG in the blood 2 days after implantation or 5 days before the first menstrual period is missed.

NOTE: The Beta HCG level is observed in nuclear medicine. This is expensive to use.

NOTE: HCG levels peak between 50 to 90 days after the last menstrual period.

b. Home pregnancy test kits are easily available and inexpensive. This test allows prenatal care to be started early.