Mam and sir my friend took beta hcg blood test two times. First on 27th October the next day after missed periods it was negative. Then she again took beta hcg blood test on 30th October that was positive. Now my question is what can be the reason for the false hcg result before? So from this above incident I am forced to ask you when to take beta hcg test after missed periods or after 2 weeks of intercourse which is more accurate and more reliable? In the above case if he would have considered that she is not pregnant then the scenario can be the worst. So please reply when is the best time to take beta hcg after 15 days of sex or after missed period?

Answered by 1 Apollo Doctors

Dr Bhanu Prakash

General Practitioner

MBBS
AFIH
Advanced certificate in critical care medicine
Fellowship in critical care medicine
10+ Yrs

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The most accurate time to take a Beta HCG test is 15 to 21 days after unprotected sex or 2 to 3 days after a missed period. In your friends case, the first test was likely too early because sometimes implantation happens late, and HCG takes time to rise. A false negative is possible if tested too soon. Thats why repeating the test like your friend did is the safest approach. Consider taking a Urine pregnancy test and a Beta HCG test to confirm the pregnancy.

Dr. Bhanu Suggests...

Take a UPT Test (Urine Pregnancy) Test or Take a Beta HCG Test Test

Book UPT Test (Urine Pregnancy) Test Book Beta HCG Test Test

Answered 09/09/2025

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