What is going on when the test paper shows one dark and one light?

Most female friends are not very good at using early pregnancy test strips. After the test, they will find that there is an abnormality on their test strips, and they will always show a dark and light situation. If this situation continues, it is best to go to the hospital for an ultrasound examination, so that you can know whether you are pregnant or whether you have an ectopic pregnancy. In either case, you should seek early treatment and deal with it.

Why is the test paper one dark and one shallow?

Early pregnancy test strips are products that help women detect whether they are pregnant. They can only be used as an initial screening test and may result in false positives or false negatives.

Instructions for use: Drop urine into the detection hole on the test paper. If a colored band appears in the control area of ​​the test paper (some test papers appear red, some test papers appear blue), it indicates a negative result, indicating that you are not pregnant. On the contrary, if a clear colored band appears in the detection area, it indicates a positive result, indicating that you are pregnant.

A positive urine test indicates β-HCG ≥ 25U/L, and the strength of the T line reflects the concentration of HCG.

1. Pregnancy:

(1) Normal pregnancy: In a normal pregnancy, HCG reaches its peak (about 50,000-100,000 U/L) 60-70 days after menopause, continues to decline for 1-2 weeks, and returns to normal 2 weeks after delivery. In the early stage, the T line deepens with the increase of HCG, and a "high concentration effect" appears when it approaches the peak (the T line weakens with the increase of HCG).

(2) Ectopic pregnancy: β-HCG will return to normal after 8-9 days of ectopic pregnancy. Urine tests may also be positive.

2. Recovery period of miscarriage or delivery: Generally, it takes 30 days and 19 days for β-HCG to return to normal after artificial abortion and spontaneous abortion respectively. It takes 12 days to return to normal in case of full-term delivery with no placenta residue. Urine tests may be positive before returning to normal.

3. Reproductive system diseases: In reproductive system diseases such as hydatidiform mole, invasive hydatidiform mole, choriocarcinoma, trophoblastic tumor, etc., β-HCG levels are abnormally elevated (>100,000 U/L). The "high concentration effect" caused by excessively high concentration weakens the T line.

4. Cross-reaction caused by homologous α-chain: In a small number of women of childbearing age, the LH peak during ovulation may cause a false positive due to homologous α-chain, especially when the hormone level is high and the urine is concentrated.

Colloidal gold pregnancy test paper urine test negative

1. Negative urine test indicates β-HCG <25U/L

(1) Non-pregnant.

(2) Ectopic pregnancy: Patients with ectopic pregnancy may have urine β-HCG levels lower than 25U/L. Therefore, in clinical practice, auxiliary diagnosis requires combination of blood β-HCG, clinical symptoms and imaging examinations.

2. High-concentration hook effect: When the β-HCG concentration is too high, a false negative may occur due to the "high-concentration hook effect".

3. Improper use of reagents: When the urine sample exceeds the MAX line or the sample addition speed is too fast, the sample does not bind to the labeled colloidal gold antibody due to the chromatographic force and directly migrates to the C and T line area. At this time, no matter how much the β-HCG content is, there will be no C and T lines.