Women's Health
hCG (pregnancy)
Human chorionic gonadotrophin (hCG) is a glycoprotein hormone produced by trophoblastic tissue, and its appearance in urine or blood is the standard biochemical marker of pregnancy. Point-of-care testing ranges from simple qualitative urine cassettes that read positive or negative to quantitative whole-blood immunoassays that report a numerical concentration near the patient.
Why it is measured
hCG confirms pregnancy quickly at the bedside, supports triage in early-pregnancy and gynaecological presentations, and is checked before imaging or medicines that could harm a pregnancy. Quantitative point-of-care hCG can also assist assessment of pregnancy of unknown location when serial values are interpreted by a clinician.
| Typical range | Qualitative urine point-of-care cassettes are typically calibrated to read positive at or above 25 mIU/mL hCG. For quantitative blood assays, non-pregnant adults usually sit below about 5 IU/L (mIU/mL); values rise markedly in pregnancy and are strongly gestation-dependent. Cut-offs and reportable ranges vary by method and manufacturer, so always interpret against the device and laboratory in use. |
|---|---|
| Sample | Qualitative tests use urine, ideally a first-morning sample for the highest concentration; some cassettes also accept serum or plasma. Quantitative point-of-care assays use a few drops of lithium- or sodium-heparinised whole blood, or plasma. |
| Turnaround | Typically about 3 to 5 minutes for qualitative urine cassettes; roughly 10 to 20 minutes for quantitative immunoassay analysers, depending on the device. |
Point of care devices that report it
- Abbott i-STAT Total Beta-hCG cartridge (quantitative, heparinised whole blood or plasma, reportable approx. 5 to 2000 IU/L)
- Radiometer AQT90 FLEX beta-hCG immunoassay analyser (quantitative, heparinised whole blood or plasma)
- Abbott (Alere) hCG Cassette urine test, 25 mIU/mL cut-off (qualitative)
- QuidelOrtho QuickVue hCG urine rapid test, 25 mIU/mL cut-off (qualitative); the QuickVue+ hCG Combo variant also accepts serum
Questions, answered
What does a positive point-of-care hCG result mean?
A positive result indicates hCG was detected at or above the device cut-off, which most commonly reflects pregnancy. It does not by itself locate or date a pregnancy, and rare non-pregnancy causes of detectable hCG exist, so results are interpreted by a clinician alongside history and, where needed, ultrasound or serial quantitative testing.
Can a point-of-care test be negative in early pregnancy?
Yes. Very early after conception, or with a dilute urine sample, hCG may sit below the test cut-off and read negative. General guidance for qualitative cassettes is to repeat with a first-morning sample after about 48 hours if pregnancy is still suspected, and a quantitative blood test may detect lower concentrations.
Why choose a quantitative point-of-care hCG over a urine cassette?
A urine cassette gives a fast positive or negative answer for confirming pregnancy. A quantitative blood assay returns a numerical concentration that, when trended over time by a clinician, can support assessment of situations such as pregnancy of unknown location. The choice depends on the clinical question, local protocol and the device available.