To detect pregnancy both blood tests and urine tests are available.
There are three types of blood tests to detect pregnancy.
1. Quantitative blood tests:
pregnancy is generally detected in blood tests by estimating the levels of
HCG( Human chorionic gonadotropin).These can be detected in blood after implantation.
Usually implantation occurs 6 to 12 days after fertilization.
Means as ovulation usually occurs in 12 to 16 days of first day of menstruation, the time of implantation will be around 20 to 26 days from first day of menstruation.
These quantitative tests can detect HCG levels even at 1 mIU/ml.
So by this test we can detect the pregnancy around 25th to 26th day of cycle in case of regular periods.
2. Qualitative
tests:
this tests can detect pregnancy at HCG levels of 25mIU/ml.They are less sensitive and by this test pregnancy can be detected after missed period.
3. Rosette
inhibition assay test:
it detects EPF(early pregnancy factor) instead of HCG. This EPF can be detected in pregnancy within 48 hours of fertilization.
So it can detect pregnancy around 16 to 18 days from first day of periods.
But this test is expensive and available in few centers only.
Urine tests to detect pregnancy:
Urine pregnancy kits usually detect pregnancy at HCG levels of 20mIU/ml to 100mIU/ml.
Their sensitivity depends on the brand and level of HCG they will detect.
They can detect pregnancy at the time of missed period or within 1 week of missed period depending on sensitivity.