Multiple Marker Screening (MMS) Requisitions
Multiple Marker Screening (MMS) - most commonly enhanced First Trimester Screening (eFTS) and Second Trimester Screening (STS) - can be performed for all singleton pregnancies. These tests are done by three provincial laboratories. Check out our interactive map to learn which of the three requisitions you should use.
Maternal Serum AFP is a screen for Open Neural Tube Defects and should only be ordered when geographical location or clinical factors limit high-quality anatomy ultrasound screening. This test does not screen for trisomy 21 or trisomy 18.
Requisition Updates
Take note that a new requisition form (version 3, May 2022) is now in use and the following changes were implemented:
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The requisition has been renamed “Multiple Marker Screening (MMS) Requisition”. |
| This change occurred to describe the specific type of prenatal screening that can be ordered using this requisition. |
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Maternal Serum Screening (MSS) has been renamed, “Second Trimester Screening” or STS. |
| This change applies to the name only, to improve understanding of when in pregnancy this screening can be done; the timing and analytes for this screen remain unchanged. |
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The option of ordering First Trimester Screening (FTS) for twin pregnancies has been removed. |
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This change occurred to reflect that First Trimester Screening (FTS) for twin pregnancies has been discontinued in Ontario. OHIP-funded Non-Invasive Prenatal Testing (NIPT) is available for all viable twin pregnancies. NIPT can be ordered using the OHIP-funded NIPT requisition with the MOH Eligibility Criteria Form. If NIPT is done, a stand-alone nuchal translucency ultrasound should always still be offered to all pregnancies, where available, due to the additional benefits that this ultrasound offers. The ultrasound can be ordered using a requisition for a facility providing NT ultrasounds. |
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A new test menu option has been added: "NT + Second Trimester Screening (NT + STS) (suspected or confirmed vanishing twin/co-twin demise only)". |
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This change was made to improve the screening process for pregnancies with a suspected or confirmed vanishing twin/co-twin demise. Select this menu option if there is a suspected or confirmed vanishing twin/co-twin demise known at the time of completing the MMS Requisition. NT + STS includes an NT ultrasound (11w2d – 13w3d) and second trimester blood sample (14w0d - 20w6d); The blood draw cannot be done until 8 weeks after demise. You can calculate the date after which the pregnant individual can have their blood drawn and record this on the requisition within the NT + STS section, where indicated. For example, if the demise was estimated to have occurred at 10w0d, the pregnant individual could have the blood draw after 18w0d (and up to a maximum of 20w6d). |
How Do I Order Multiple Marker Screening?
Step-by-step Instructions for ordering each screening modality can be found below:
Which Multiple Marker Screen Should I Offer?
The Multiple Marker Screening options that are possible for a pregnant individual in your care depend on gestational age, availability of nuchal translucency (NT) ultrasound, and whether there is a history of a vanishing twin / co-twin demise. Please select the statement that applies to the pregnant individual in your care to learn which options apply for them.
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Pregnant individual is in the first trimester of pregnancy |
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The optimal Multiple Marker Screening modality for most singleton pregnancies is enhanced First Trimester Screening (done between 11 weeks 2 days to 13 weeks 3 days gestation). Special scenarios:
Multiple Marker Screening is not recommended when a NIPT result is pending or NIPT results were conclusively reported as "high risk" or "low risk". Individuals who have inconclusive NIPT result(s) can have Multiple Marker Screening as an alternative test. |
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Pregnant individual is in the second trimester of pregnancy |
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The Multiple Marker Screening modality available for singleton pregnancies in the second trimester is "Second Trimester Screening" (done between 14 weeks 0 days to 20 weeks 6 days gestation). Second Trimester Screening is also possible for confirmed or suspected vanishing twin/co-twin demise scenarios. Multiple Marker Screening is not recommended when a NIPT result is pending or NIPT results were conclusively reported as "high risk" or "low risk". Individuals who have inconclusive NIPT result(s) can have Multiple Marker Screening as an alternative test. |
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Pregnant individual is in the third trimester of pregnancy |
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There are no Multiple Marker Screening modalities available for singleton pregnancies in the the third trimester. The prenatal screening option at this stage in the pregnancy is Non-Invasive Prenatal Testing (OHIP-funded or private-pay). |
Every pregnant individual in your care should be provided with the option of Non-Invasive Prenatal Testing (OHIP-funded or private-pay, depending on the scenario), as an alternative screen to Multiple Marker Screening.
People have the option of declining any type of prenatal screening for trisomy 21 and trisomy 18. These individuals can still choose to have a stand-alone 11-14 week ultrasound (including nuchal translucency measurement where available), and a 18-22 week ultrasound.
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