2ndtrimester3screenserplimp
A blood test performed during pregnancy to screen for certain birth defects and chromosomal abnormalities.
{"Screens for neural tube defects like spina bifida","Helps assess risk for Down syndrome and other chromosomal conditions","Performed between 15-20 weeks of pregnancy","Results indicate risk level, not a definitive diagnosis","A positive screen means further testing is needed"}
Key facts at a glance
- LOINC
- 49572-1
- Short code
- 2nd trimester 3 screen SerPl-Imp
- Synonyms
- 2nd trimester 3 screen SerPl-Imp
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0
- Ref high
- 17
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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
What is the Second Trimester Triple Screen?
The second trimester triple screen is a blood test that measures three substances in a pregnant woman's blood: alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and estriol. These are substances produced by the fetus and the placenta during pregnancy. By measuring their levels, healthcare providers can estimate the risk of certain birth defects and genetic conditions.
What Does This Test Screen For?
This screening test helps identify the risk of: Neural tube defects such as spina bifida (an opening in the baby's spine or brain), Down syndrome (trisomy 21), and other chromosomal abnormalities. It does not provide a definitive diagnosis but indicates whether further diagnostic testing is recommended.
How is the Test Performed?
A healthcare provider will draw a small blood sample from your arm. The sample is then sent to a laboratory for analysis. The test is typically done between 15 and 20 weeks of pregnancy. Results are usually available within a few days to a week.
Understanding Your Results
Results are reported as screen positive or screen negative. A 'positive' result means your baby has a higher risk for certain conditions, but it does NOT mean your baby definitely has a problem. Similarly, a 'negative' result does not guarantee a healthy baby. Your healthcare provider will explain your results and discuss whether additional tests such as ultrasound or amniocentesis are recommended.
Reference range
NCBI: NSE 0-17 ng/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.
◆Associated findings2
Frequently asked questions
Is the triple screen mandatory?
Does a positive result mean my baby has a birth defect?
Can the test tell me the sex of my baby?
What factors can affect the test results?
What's the difference between screening and diagnostic tests?
Sources
- 1
- 2
- 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 17, 2026. · Read our editorial policy