Is one line accurate if menstruation is over 20 days late?
Apr 10, 2023
Source: Cainiu Health
Dr. Lv Aiming
Introduction
A negative result (one line) on a pregnancy test after a 20-day menstrual delay is generally accurate, but not absolutely so. As long as the testing method is correct, the results are usually highly reliable. However, if the early pregnancy test strip or pregnancy test stick is used incorrectly or an expired test strip is used, the result may be inaccurate. Additionally, if unprotected sexual intercourse occurred during the delayed period, pregnancy could have occurred, but the test strip might not yet detect it due to the short duration of pregnancy.
A negative result (one line) on a pregnancy test after a 20-day menstrual delay is generally accurate, but not absolutely so. There may still be factors leading to inaccuracy, and a blood HCG test is recommended for confirmation.
1. Accurate
After a delay of over 20 days, using a home pregnancy test strip or pregnancy test stick showing one line indicates a negative result. Provided the testing method is correct, such results are usually highly reliable, indicating no pregnancy and suggesting the cause is menstrual irregularity.
2. Inaccurate
A single line after a delayed period may sometimes be inaccurate. Incorrect use of the pregnancy test strip or stick, or using an expired test kit, can affect the accuracy of the result. Additionally, irregular ovulation may alter the timing; if unprotected intercourse occurred during the delayed period, pregnancy could still happen. However, if conception was recent, the HCG levels might not yet be high enough to be detected by the test, resulting in a false-negative.
After obtaining a negative test result following a missed period, it's best to confirm with a blood HCG test. If pregnancy is ruled out, further examinations such as pelvic ultrasound and sex hormone panel (six items) should be performed to identify the cause of the delay and guide appropriate treatment.
