Estriol Unconjugated / Free (uE3) Test
Short Name: uE3
Also known as: Free Estriol Test, Unconjugated Estriol Test, uE3 Test, Serum Free Estriol, Maternal Estriol Test
Estriol Unconjugated / Free (uE3) Test test available at DNA Labs India for ₹1,439. Uses Chemiluminescent Immunoassay on Serum samples. Results in Results are typically available within 24 hours. Same-day reporting may be available depending on sample receipt time.. Free home collection in 300+ cities across India.
🩺 Medically Reviewed By
Dr Ramarao Paidisetty
Consultant Biochemist · Reg: 21504
Last reviewed: September 7, 2026
Overview
The primary purpose of the Estriol Unconjugated / Free (uE3) test is to serve as a second-trimester screening marker for fetal chromosomal abnormalities. It is used in conjunction with AFP, hCG, and optionally inhibin A as part of the triple or quad marker screening panel to calculate the statistical risk of conditions such as Down syndrome (Trisomy 21) and Trisomy 18. The test also helps assess fetal–placental endocrine function and can aid in identifying pregnancies at increased risk for certain fetal conditions requiring further diagnostic evaluation.
- Test Code
- 549
- CPT Code
- 82677
- ICD Code
- Z36.0
- Price
- ₹1,439
- Sample Type
- Serum
- Result Time
- Results are typically available within 24 hours. Same-day reporting may be available depending on sample receipt time.
- Fasting Required
- No
- Method
- Chemiluminescent Immunoassay
Sample Collection
No fasting or special preparation is required. Inform your healthcare provider about any medications, supplements, or medical conditions. Ensure your gestational age has been accurately determined via ultrasound, as result interpretation depends on correct dating.
Method: Venous blood draw
Laboratory Analysis
A trained phlebotomist will clean the antecubital fossa, apply a tourniquet, and insert a sterile needle into a vein in your arm to collect approximately 2 mL of blood into a Serum Separator Tube (SST). The procedure typically takes less than five minutes.
Report Delivery
Pressure will be applied to the puncture site with a cotton ball and bandage. Minor bruising may occur. You may resume normal activities immediately. There are no activity restrictions following the blood draw.
Timeline: Results are typically available within 24 hours. Same-day reporting may be available depending on sample receipt time.
Patient Instructions
About This Test
Who Should Get This Test
The primary purpose of the Estriol Unconjugated / Free (uE3) test is to serve as a second-trimester screening marker for fetal chromosomal abnormalities. It is used in conjunction with AFP, hCG, and optionally inhibin A as part of the triple or quad marker screening panel to calculate the statistical risk of conditions such as Down syndrome (Trisomy 21) and Trisomy 18. The test also helps assess fetal–placental endocrine function and can aid in identifying pregnancies at increased risk for certain fetal conditions requiring further diagnostic evaluation.
How to Prepare
- Collect 2 mL (minimum 1 mL) of venous blood into a Serum Separator Tube (SST)
- Gently invert the tube 5–6 times to ensure proper mixing
- Allow the blood to clot for 30 minutes before centrifugation
- Separate serum from cells
- Ship the sample refrigerated (2–8°C) or frozen (−20°C)
Doctor's Notes
Reviewed by Dr Ramarao Paidisetty — MBBS, MD (Biochemistry) · Reg. No. 21504
"The unconjugated estriol (uE3) test provides valuable insight into fetal–placental endocrine function. Estriol synthesis requires contributions from both the fetal adrenal glands and the fetal liver before final aromatization by the placenta. Low second-trimester uE3 levels are a well-established biochemical marker for increased risk of Trisomy 21 and Trisomy 18. I recommend this test as part of the comprehensive second-trimester screening panel for all pregnant women, particularly those with risk factors or abnormal first-trimester screening results."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Hemolyzed sample
- Insufficient sample volume (less than 1 mL)
- Improperly labeled or unlabeled specimen
- Sample not stored or transported at recommended temperature
- Clotted blood in anticoagulant tube (if applicable)
Understanding Your Results
uE3 levels within the expected range for gestational age. When combined with other markers, this suggests a lower statistical risk for the screened chromosomal abnormalities. Continue routine prenatal care as advised by your healthcare provider.
Range: Normal (0.5–2.0 MoM)
Low uE3 levels may be associated with an increased risk of Down syndrome (Trisomy 21), Trisomy 18, Smith-Lemli-Opitz syndrome, steroid sulfatase deficiency, or fetal demise. Your healthcare provider may recommend further diagnostic testing such as amniocentesis, chorionic villus sampling (CVS), or non-invasive prenatal testing (NIPT).
Range: Low (<0.5 MoM)
Elevated uE3 levels may suggest a multiple gestation or may not be clinically significant in isolation. Clinical correlation with other screening markers, ultrasound findings, and gestational age is recommended.
Range: High (>2.0 MoM)
Consult your healthcare provider if your uE3 test result falls outside the expected range for your gestational age, or if the combined screening result indicates an elevated risk for chromosomal abnormalities. Your doctor may recommend additional diagnostic tests such as amniocentesis, chorionic villus sampling (CVS), or non-invasive prenatal testing (NIPT) for definitive evaluation. Do not make clinical decisions based on a single screening marker.
Limitations
- ⚠This is a screening test and does not provide a definitive diagnosis of chromosomal abnormalities
- ⚠Results must be interpreted alongside other markers (AFP, hCG, inhibin A) and clinical information
- ⚠Accuracy is dependent on precise gestational age determination
- ⚠Does not detect all chromosomal or structural fetal abnormalities
- ⚠False-positive and false-negative results are possible
- ⚠An elevated risk result requires confirmatory diagnostic testing such as amniocentesis or NIPT
Risks & Considerations
- ●Minimal risk associated with standard venous blood draw
- ●Possible minor bruising or tenderness at the puncture site
- ●Rare risk of infection at the blood draw site
- ●Slight chance of feeling dizzy or lightheaded during or after blood collection
Interfering Factors
- ●Inaccurate gestational age dating
- ●Multiple pregnancy (twins, triplets)
- ●Maternal insulin-dependent diabetes mellitus
- ●Maternal smoking
- ●Maternal obesity
- ●Use of corticosteroids or certain hormonal medications
- ●Conception via in-vitro fertilization (IVF)
Compare With Similar Tests
| Test | Estriol Unconjugated / Free (uE3) Test | Triple Marker Screen | Quad Marker Screen | Combined First Trimester Screen | Non-Invasive Prenatal Testing (NIPT) |
|---|---|---|---|---|---|
| Comparison | Estriol Unconjugated / Free (uE3) Test |
Frequently Asked Questions
What is the Estriol Unconjugated / Free (uE3) test?
Why is the uE3 test recommended during pregnancy?
At what gestational age should the uE3 test be performed?
What does a low uE3 level indicate?
What does a high uE3 level indicate?
Is fasting required before the uE3 test?
What is the cost of the uE3 test at DNA Labs India?
How is the blood sample collected for the uE3 test?
When will I receive my uE3 test results?
Can the uE3 test alone diagnose Down syndrome?
What other tests are performed alongside the uE3 test?
Is home sample collection available for the uE3 test?
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