7 doctors weighed in:

How many days after intercourse will a blood pregnancy test be accurate? (Irregular periods)

7 doctors weighed in
Dr. Robert Kwok
Pediatrics
5 doctors agree

In brief: 2-3 weeks

By 3 weeks after sex (2-3 weeks after conception) both the home urine pregnancy test and the clinic blood pregnancy test are accurate.
The result is very reliable by that time, regardless of whether or not a woman knows when her last menstrual period was. Patience is a wonderful virtue. If one tests too early, a positive is likely real, but a negative may be due to testing too early.

In brief: 2-3 weeks

By 3 weeks after sex (2-3 weeks after conception) both the home urine pregnancy test and the clinic blood pregnancy test are accurate.
The result is very reliable by that time, regardless of whether or not a woman knows when her last menstrual period was. Patience is a wonderful virtue. If one tests too early, a positive is likely real, but a negative may be due to testing too early.
Thank
Dr. Gurmukh Singh
Pathology
1 doctor agrees

In brief: 3 weeks

Conception occurs within day or so of the sex.
It takes about 3 weeks for the embryo to make enough HCG for a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow instructions for the test carefully.

In brief: 3 weeks

Conception occurs within day or so of the sex.
It takes about 3 weeks for the embryo to make enough HCG for a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow instructions for the test carefully.
Thank
Dr. Roger Duvivier
Obstetrics & Gynecology

In brief: "After intercourse"?

If genito-sexual relations and ejaculation by a fertile man occured about the time of ovulation of a woman who is healthy,whose tubes-uterus are normal.
.. a"blood pregnancy test" is likely to become positive 10 to 12 days after fertilization (not after intercourse).
If you have"irregular periods",you probably ovulate irregularly if at all; therefore it may be more difficult to answer your concern

In brief: "After intercourse"?

If genito-sexual relations and ejaculation by a fertile man occured about the time of ovulation of a woman who is healthy,whose tubes-uterus are normal.
.. a"blood pregnancy test" is likely to become positive 10 to 12 days after fertilization (not after intercourse).
If you have"irregular periods",you probably ovulate irregularly if at all; therefore it may be more difficult to answer your concern
Thank
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