Prenatal PAPP-A (Pregnancy-Associated Plasma Protein-A) with Free β-Human Chorionic Gonadotropin (β-hCG) Ratio
This test measures two proteins involved in early pregnancy to help assess the risk of certain fetal conditions.
["A PAPP-A/β-hCG ratio may help identify potential risks during early pregnancy that require further evaluation."]
Key facts at a glance
- LOINC
- 49030-0
- Short code
- Ts 21 risk-age+PAPPA+HCG+NT Fetus
- Synonyms
- Ts 21 risk-age+PAPPA+HCG+NT Fetus
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0
- Ref high
- 5
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84702
- SNOMED
- 275917004
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Your healthcare provider may recommend this test during the first trimester (around 10–14 weeks of pregnancy) to screen for chromosomal abnormalities, such as Down syndrome, or other conditions that may affect fetal development. It is often performed as part of a combined screening test that includes ultrasound measurements.
What the Test Measures
PAPP-A (Pregnancy-Associated Plasma Protein-A) and β-hCG (beta-human chorionic gonadotropin) are proteins produced by the placenta. The ratio of these proteins helps evaluate the likelihood of certain genetic or developmental concerns.
Sample Collection and Preparation
A blood sample is drawn from a vein in your arm. The blood is processed to separate the plasma, which contains the proteins measured in this test.
What to Expect Before the Test
No special preparation is needed, but inform your healthcare provider if you are taking medications or have any conditions that might affect test results.
Reference range
Non-pregnant: <5 mIU/mLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated or low PAPP-A/β-hCG ratios may indicate an increased risk of chromosomal abnormalities (e.g., Down syndrome, trisomy 18) or other pregnancy complications. While not a definitive diagnostic test, it provides important screening information that can guide further testing or monitoring.
Short name
PAPP-A/β-hCG Ratio Screening
Frequently asked questions
What does a low or high ratio mean?
Does this test replace an ultrasound?
Can I get this test if I’m not pregnant yet?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy