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Pregnancy Test Serum

Pregnancy Biomarker

Sample Needed

Collection Type: Blood

Body System

Related System: Pregnancy

Overview

The serum pregnancy test measures human chorionic gonadotropin (hCG), a hormone produced by the placenta’s syncytiotrophoblast cells shortly after embryo implantation. A serum assay can be qualitative (positive/negative) or quantitative (beta-hCG level in mIU/mL) and detects pregnancy earlier and more precisely than urine tests. It is used to confirm intrauterine pregnancy and to help evaluate suspected ectopic pregnancy, failed pregnancy (miscarriage), molar pregnancy, or hCG-secreting tumors. Symptoms prompting testing include a missed period, nausea/vomiting, breast tenderness, pelvic pain or vaginal bleeding. Results vary by sex and age: nonpregnant women and men have very low/undetectable hCG, pregnant women show progressively higher levels that depend on gestational age; postmenopausal women may show low-level elevations.

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Test Preparation

No special preparation is required

Why Do I Need This Test

Profile: Pregnancy - Symptoms: missed periods, nausea, breast tenderness, pelvic pain/bleeding - Diagnoses/monitoring: confirms pregnancy, monitors early pregnancy viability, detects ectopic or molar pregnancy, follows treatment of trophoblastic disease or hCG-secreting tumors - Reasons for abnormal levels: early pregnancy, multiple gestation, molar pregnancy, ectopic pregnancy, miscarriage, hCG-producing tumors, interfering medications or antibodies - Biological meaning: high levels indicate pregnancy or trophoblastic activity; low or falling levels suggest failed pregnancy or resolving pregnancy - Behaviors: recent fertility treatments or hCG injections and recent pregnancy loss can affect results - Family history: prior molar pregnancy, recurrent ectopic pregnancy, or familial tumor syndromes may prompt earlier/more frequent testing

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Understanding Test Results

<5 mIU/mL: generally negative for pregnancy in nonpregnant adults.
In men or nonpregnant women, any detectable hCG should prompt evaluation for hCG-secreting tumors.
5–25 mIU/mL: indeterminate/borderline repeat quantitative testing in 48–72 hours to look for a rising pattern; low early pregnancy may fall in this range.
>25 mIU/mL: consistent with pregnancy (positive); quantitative values should be interpreted by gestational age.
In early viable intrauterine pregnancy, hCG typically rises by ~50–100% every 48 hours; slower rises suggest ectopic pregnancy or impending miscarriage.
Very high values (often >100,000–200,000 mIU/mL) can be seen with molar pregnancy or multiple gestation.
Falling or plateauing levels indicate miscarriage or successful treatment of trophoblastic disease.
Rare false negatives can occur at extremely high hCG due to the “hook effect”; rare false positives may result from heterophile antibodies or recent hCG administration.
Repeat testing and ultrasound correlation are often required.

Normal Range

0-5 mIU/mL

FAQs

Q: Is serum used for pregnancy tests?

A: Yes. Blood (serum) pregnancy tests detect human chorionic gonadotropin (hCG) and are offered as qualitative (yes/no) or quantitative (beta-hCG) assays. Serum tests are more sensitive than urine, can detect pregnancy earlier, and measure hCG levels for dating or monitoring. They require a blood draw and laboratory processing; results are usually available within hours to a day.

Q: Is a serum pregnancy test more accurate?

A: Yes. A serum (blood) beta‑hCG test is more sensitive and quantitative than a urine test, detecting lower hCG levels and often identifying pregnancy earlier. It gives exact hCG values useful for confirming pregnancy and monitoring viability or ectopic risk. Home urine tests are reliable after a missed period but are less sensitive and more affected by timing and urine dilution.

Q: What is a normal serum pregnancy level?

A: Serum pregnancy testing measures the beta‑hCG hormone. A level <5 mIU/mL is considered negative, 5–25 mIU/mL is indeterminate, and >25 mIU/mL is generally positive. hCG varies by gestation: about 5–50 mIU/mL at ~3 weeks, rising to ~1,080–56,500 mIU/mL by ~6 weeks and peaking around 8–11 weeks. Interpret with clinical context and repeat testing.

Q: What is a positive hCG serum?

A: A positive serum hCG means human chorionic gonadotropin is detected in the blood. It usually indicates pregnancy—hCG is produced after embryo implantation—and quantitative serum tests can detect pregnancy earlier and monitor rising or falling levels. Less commonly, positive results occur with certain tumors, recent hCG injections, or molar pregnancy. Follow-up testing and clinical correlation are required.

Q: Can a serum pregnancy test be wrong?

A: Serum (blood) pregnancy tests are highly accurate and detect hCG at very low levels, but they can rarely be wrong. False negatives happen if tested too early, with very low hCG, or due to lab error; false positives can follow recent pregnancy loss (chemical pregnancy), certain medications, rare hCG-secreting conditions, or assay interference. Repeat testing, clinical evaluation, or ultrasound can confirm results.

Q: Which serum is pregnancy safe?

A: Pregnancy-safe serums commonly include hyaluronic acid, vitamin C (L-ascorbic acid), niacinamide, azelaic acid, peptides and ceramide-rich hydrators. Low‑strength AHAs (lactic/glycolic) are usually acceptable; avoid professional chemical peels. Do not use retinoids (retinol, tretinoin, adapalene), oral isotretinoin, high‑concentration salicylic acid treatments or hydroquinone. Always check ingredients and consult your healthcare provider.