Are early pregnancy test results accurate?
Disease description:
I've recently experienced a delay in my menstrual period, and I'm worried that I might be pregnant. I'd like to first test myself using a pregnancy test strip. I want to know, are the results of early pregnancy test strips accurate?
Doctor's answer (1)
Dr. Zhao Xiaodong
The accuracy of early pregnancy test results is influenced by various factors, but generally speaking, these tests are quite accurate.
1. Testing Principle: Early pregnancy tests primarily determine whether a woman is pregnant by measuring the level of human chorionic gonadotropin (hCG) in urine. hCG is a glycoprotein secreted by the placental trophoblastic cells after pregnancy. It typically appears in urine within a few days of conception, and its concentration increases progressively with the duration of pregnancy.
2. Factors Affecting Accuracy:
- Time since missed period: If the time since the last menstrual period is short—such as only 1–2 days overdue—the test's accuracy may be reduced.
- Urine dilution: Excessive fluid intake can dilute the urine, potentially affecting the accuracy of the result.
- Time of testing: hCG concentration in urine is usually highest in the morning; therefore, it is recommended to use first-morning urine for testing.
