Sign in →

Test Code MS1TRI Maternal Screen First Trimester, Serum, Lab2267

Important Note

Please accompany sample with Iowa Maternal Screen Test Request Form.


First trimester screening test for DS and T18, drawn between 10 weeks 0 days and 13 weeks 6 days gestation when Crown Rump Length (CRL) is 32-80 mm.


Incorrect information, especially incorrect dating, will result in inaccurate risk assessment.  Requires nuchal translucency (NT) measurement by sonographer certified by FMF or NTQR.  The sonographer's name, certification number, and certifying organization must be on file with the laboratory to submit an NT measurement.  Call 319-335-4056 the first time a sonographer is submitting an NT measurement with a test request.  If NT is unobtainable, order Integrated Screen.  The following information is required for test interpretation: Ultrasound date AND crown rump length (CRL) measurement, an NT measurement obtained between 10 weeks and 13 weeks 6 days, patient's date of birth, current weight, patient's race, and for IVF pregnancies, the age of the egg donor at time of egg retrieval.  This test cannot be performed on multiples.  Detection rates: 83% Down Syndrome, 80% Trisomy 18 False positive rate: 5%.  Note: if this test is performed, it is recommended that a NTD screen be ordered in the second trimester. 

Performing Laboratory

State Hygenic Laboratory

Coralville, Iowa


Specimen Requirements

Container/Tube: Gold-top serum gel tube or plain red-top tube

Specimen: 1 mL of serum

Transport Temperature: Refrigerate and send specimen with cold pack.

Collection Instructions:  Dating by ultrasound crown rump length (CRL).  Serum sample drawn in the first trimester when the CRL is 32-80 mm.  Incorrect dating will result in inaccurate risk assessment.

Stability: Specimen must be received within 9 days of collection.




Specimen Minimum Volume

1 mL of serum


Reference Values

MoM values for hCG and Papp-A Risk Values for Down Syndrome and trisomy 18 Screen Cutoff established for test Interpretation/Recommended Action: Negative/No further action Positive/ Level II Ultrasound, counseling and consideration for diagnostic testing.

Day (s) Test Set Up

Monday through Friday

Test Classification and CPT coding


84163 Papp-A

Rejected due to:


Samples not collected within the required gestational age for the test requested.