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Test Code QUAD1 Quad Screen (Second Trimester) Maternal, Serum

Reporting Name

QUAD SCRN (2nd Tri) Maternal, S

Useful For

Prenatal screening for open neural tube defect (alpha-fetoprotein only), trisomy 21 (alpha-fetoprotein, human chorionic gonadotropin, estriol, and inhibin A) and trisomy 18 (alpha-fetoprotein, human chorionic gonadotropin, and estriol)

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type


Necessary Information

In order to provide the best results, either answer the order entry questions or provide the required information using the Second Trimester Maternal Screening Alpha-Fetoprotein (AFP)/QUAD Screen Patient Information (T595) (see Special Instructions).

Specimen Required


Preferred: Red top

Acceptable: Serum gel

Specimen Volume: 1 mL

Collection Instructions:

1. Do not draw specimen after amniocentesis as this could affect results.

2. Centrifuge immediately

Additional Information:

1. For an assessment that includes neural tube defect results, gestational age must be between 15 weeks, 0 days and 22 weeks, 6 days.

2. Assessments for trisomy 21 (Down syndrome) and trisomy 18 (Edwards syndrome) only are available between 14 weeks, 0 days and 22 weeks, 6 days.

3. Initial or repeat testing is determined in the laboratory at the time of report and will be reported accordingly. To be considered a repeat test for the patient, the testing must be within the same pregnancy and trimester, with interpretable results for the same tests, and both tests are performed at Mayo Clinic.

4. Maternal Serum Screening patient education brochure (T522) is available upon request.

Specimen Minimum Volume

0.75 mL

Testing Algorithm

See Prenatal Aneuploidy Screening and Diagnostic Testing Options in Special Instructions

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 7 days
  Frozen  90 days

Reference Values


An AFP multiple of the median (MoM) <2.5 is reported as screen negative. AFP MoMs ≥2.5 (singleton and twin pregnancies) are reported as screen positive. 



Calculated screen risks <1/270 are reported as screen negative, risks ≥1/270 are reported as screen positive.



Calculated screen risks <1/100 are reported as screen negative, risks ≥1/100 are reported as screen positive.


An interpretive report will be provided.

Day(s) and Time(s) Performed

Monday through Friday; 8 a.m.-4:30 p.m.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
QUAD1 QUAD SCRN (2nd Tri) Maternal, S 48800-7


Result ID Test Result Name Result LOINC Value
7058 Recalculated Maternal Serum Screen 32399-8
113146 Results Summary 32399-8
10334 Down syndrome screen risk estimate 43995-0
10335 Down syndrome maternal age risk 49090-4
10337 Trisomy 18 screen risk estimate 43994-3
113147 Neural tube defect risk estimate 48803-1
10351 AFP 83073-7
113148 AFP MoM 23811-3
601921 AFP MoM (14,0-14,6) 23811-3
10352 uE3 2250-9
113149 uE3 MoM 21264-7
10353 hCG, TOTAL 83086-9
113150 hCG, TOTAL MoM 23841-0
113151 INHIBIN MoM 36904-1
10354 INHIBIN 2478-6
10356 INTERPRETATION 49092-0
10248 Additional comments 48767-8
3009 Specimen collection date 33882-2
7823 Maternal date of birth 21112-8
7834 Calculated age at EDD 43993-5
26717 Maternal Weight 29463-7
26718 Maternal Weight 29463-7
IDD Insulin dependent diabetes 44877-9
RACE1 Patient race 21484-1
SMKNG Current cigarette smoking status 64234-8
10054 EDD by U/S scan 11781-2
7203 GA on collection by U/S scan 11888-5
7753 EDD by LMP 11779-6
7204 GA on collection by dates 11885-1
7830 GA used in risk estimate 21299-3
MULTF Number of Fetuses 55281-0
CHOR_ Number of Chorions 92568-5
IVFP IVF pregnancy 47224-1
PRHIS Prev Down (T21) / Trisomy Pregnancy 53826-4
PRNTD Prev Pregnancy w/ Neural Tube Defect 53827-2
PTNTD Patient or father of baby has a NTD 53827-2
INTL Initial or repeat testing 77202-0
DRPHN Physician Phone Number 68340-9

Clinical Reference

1. Wald NJ, Cuckle HS, Densem JW, Stone RB: Maternal serum unconjugated oestriol and human chorionic gonadotrophin levels in pregnancies with insulin-dependent diabetes: implications for screening for Down's syndrome. Br J Obstet Gynaecol. 1992 Jan;99(1):51-53

2. American College of Obstetricians and Gynecologists: Practice Bulletin No. 163: Screening for Fetal Aneuploidy. Obstet Gynecol. 2016 May;127(5):e123-137

3. Malone FD, Canick JA, Ball RH, et al: First-trimester or second-trimester screening, or both, for Down's syndrome. N Engl J Med. 2005 Nov 10;353(19):2001-2011

4. Wald NJ, Rodeck C, Hackshaw AK, et al: SURUSS in perspective. Semin Perinatol. 2005;29:225-235

5. Rudnicka AR, Wald NJ, Huttly W, Hackshaw AK: Influence of maternal smoking on the birth prevalence of Down syndrome and on second trimester screening performance. Prenat Diagn. 2002 Oct;22(10):893-897

6. Zhang J, Lambert-Messerlian G, Palomaki GE, Canick JA: Impact of smoking on maternal serum markers and prenatal screening in the first and second trimesters. Prenat Diagn. 2011 Jun;31(6):583-588

7. Yarbrough ML, Stout M, Gronowski AM: Ch 69 Pregnancy and Its Disorders. In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:1655-1696

Method Description

This 4-marker screen includes alpha-fetoprotein (AFP), estriol (uE3), human chorionic gonadotropin (total beta-hCG: ThCG), and inhibin A. Analyte values are compared to median values at a given gestational age and multiple of the median (MoM) results obtained. The MoM results are used in a multivariate algorithm that includes the mother's age to derive risk factors for trisomy 21 (Down syndrome) and trisomy 18 (Edwards syndrome). The screen for neural tube defects (NTD) uses the AFP MoM only. An interpretive report will be provided. The Beckman Access AFP, ThCG, uE3, and inhibin A assays are automated immunoenzymatic assays with paramagnetic separation and chemiluminescent detection.(Package insert: Beckman Coulter Access AFP, Total bhCG, Unconjugated Estriol, and Inhibin A. Beckman Coulter; 2019)

Analytic Time

1 day

Reject Due To

Gross hemolysis Reject
Gross lipemia OK
Gross icterus OK

Method Name

Immunoenzymatic Assay

Secondary ID