What is hCG?
Human Chorionic Gonadotropin (hCG) is a hormone produced after a fertilized egg implants in the uterus. This hormone is the basis for pregnancy tests, as its presence is a reliable indicator of pregnancy.
Pregnancy Tests Types
Two main types of pregnancy tests exist: urine tests, available over-the-counter, and blood tests, conducted by healthcare providers. Both detect hCG, but blood tests can identify pregnancy earlier and measure the hCG concentration.
Urine Test Sensitivity
Over-the-counter urine pregnancy tests vary in sensitivity. Some can detect hCG as low as 20 mIU/ml, making them capable of identifying pregnancy about a week after conception.
Immunoassay Test Principle
Most home tests use lateral flow immunoassays. When urine is applied, it mobilizes antibodies colored with gold or latex, which bind to hCG if present, indicating a positive result on the test strip.
False Positives and Negatives
Several factors can cause false positives, including certain medications, diseases, and the presence of pituitary hCG. Conversely, testing too early or with diluted urine can lead to false negatives.
Digital Advancements
Digital tests provide clear results without interpreting lines. They use a sensor to detect the hormone's presence, which triggers an electronic message, such as 'pregnant' or 'not pregnant'.
Test Timing Matters
The best time to take a urine pregnancy test is the first morning urine when hCG levels are most concentrated. Waiting at least a week after a missed period increases reliability.
What indicates pregnancy in tests?
Presence of hCG hormone
Early morning urine sample
Digital sensor activation
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