Test Catalog

Test ID: SEQB    
Sequential Maternal Screening, Part 2, Serum

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Specimen Type Describes the specimen type validated for testing


Advisory Information

Do not order this test unless test SEQA / Sequential Maternal Screening, Part 1, Serum has already been ordered.


If a standalone second-trimester screen is desired, order QUAD1 / Quad Screen (Second Trimester) Maternal, Serum.


If a stand-alone neural tube defect risk assessment is desired, order MAFP1 / Alpha-Fetoprotein (AFP), Single Marker Screen, Maternal, Serum.

Additional Testing Requirements

Sequential maternal screening is a 2-step test that includes a first-trimester sample (SEQA / Sequential Maternal Screening, Part 1, Serum) and a second-trimester sample (SEQB / Sequential Maternal Screening, Part 2, Serum).

Necessary Information

Collection date is required.

Specimen Required Defines the optimal specimen required to perform the test and the preferred volume to complete testing


Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Collect blood between 15 weeks, 0 days and 22 weeks, 6 days. Do not collect blood after performing amniocentesis, as that may lead to an artificially increased serum alpha-fetoprotein level and unreliable results.

2. Centrifuge and aliquot within 2 hours of collection.

Special Instructions Library of PDFs including pertinent information and forms related to the test

Specimen Minimum Volume Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.5 mL

Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject
Gross lipemia OK
Gross icterus OK

Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen TypeTemperatureTimeSpecial Container
SerumRefrigerated (preferred)7 days
 Frozen 90 days