(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.