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Test Code BLOD1288 First Trimester Maternal Screen, Serum

Additional Codes

Mayo Test Code: 1STT1


Advisory Information


This test does not screen for neural tube defects. If risk assessment for neural tube defects is desired, collect specimen between 15 weeks, 0 days and 22 weeks, 6 days for an AFP single marker screen, MAFP1 / Alpha-Fetoprotein (AFP), Single Marker Screen, Maternal, Serum.

 

QUAD screening (QUAD1 / Quad Screen [Second Trimester] Maternal, Serum) is not recommended following first-trimester screening.



Necessary Information


Approval to send specimen for first-trimester screening is required and may take up to 5 business days to complete. Nuchal translucency (NT) measurements are only accepted from NT-certified sonographers. Do not send specimen to Mayo Clinic Laboratories if the sonographer is not NT-certified or before completing the application process. See Maternal Screening: Sonographer Approval Process link or complete the NT/CRL Data for First Trimester/Sequential Maternal Screening form in Special Instructions.



Specimen Required


Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions: Centrifuge and aliquot within 2 hours of collection

Additional Information:

1. Blood draw and ultrasound must be completed between 10 weeks, 0 days and 13 weeks, 6 days, which corresponds to a crown-rump length (CRL) range of 31 to 80 mm.

2. 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 test and both tests are performed at Mayo Clinic.


Forms

First Trimester/Sequential Maternal Screening Patient Information (T593) is required; see Special Instructions.

Useful For

Prenatal screening for Down syndrome and trisomy 18

Testing Algorithm

See Prenatal Aneuploidy Screening and Diagnostic Testing Options in Special Instructions.

Method Name

Immunoenzymatic Assay

Specimen Type

Serum

Specimen Minimum Volume

0.75 mL

Specimen Stability Information

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

Reject Due To

Gross hemolysis Reject
Gross lipemia OK

Reference Values

DOWN SYNDROME

Calculated screen risks <1/230 are reported as screen negative.

Risks ≥1/230 are reported as screen positive.

 

TRISOMY 18

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

Risks ≥1/100 are reported as screen positive. A numeric risk for trisomy 18 risk is provided with positive results on non-diabetic, non-twin pregnancies.

An interpretive report will be provided.

Day(s) and Time(s) Performed

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

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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

81508