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Provincially Funded and Privately Paid Screening Tests

All pregnant women in BC with Medical Services Plan (MSP) coverage (BC Services Cardcan choose to have prenatal genetic screening. How far along you are in your pregnancy, your age, health, family history, and whether or not you are carrying more than one baby will influence which screening tests are available to you. More information regarding the prenatal screening tests available to women in BC can be found on the FAQs page under the question "What are the different prenatal screens?" 

Some women may choose to pay privately for a screen not available in the BC public medical system. There are two options: one is called First Trimester Screening (FTS) and the other is called Non-Invasive Prenatal Testing (NIPT).

  • FTS involves the NT (nuchal translucency) ultrasound and one blood test. The ultrasound and blood test both occur in the first trimester - between 11 and just under 14 weeks. A result is available on the same day as the ultrasound.
  • NIPT involves one blood test which can be done as early as 10 weeks based on a dating ultrasound.

Regardless of the chosen test, a screen positive result will require a diagnostic test (amniocentesis or chorionic villi sampling) to get a definite answer. This is true even if the screening test is NIPT, which is the most accurate screening test.

The tests can be compared from many points of view:


  • Performance of the tests: Each test has a chance of having a false positive result. In other words, screening positive when in fact the baby does not have Down syndrome. The NIPT has the lowest false positive rate of all the screening tests, followed by IPS. The chance of a false positive is comparable for SIPS and FTS. Regardless of which screening test is done (IPS, SIPS, FTS, NIPT), women with a negative result still have a chance of having a baby with Down syndrome (called a false negative result). But that chance is lower for a negative NIPT result than with a IPS/SIPS and FTS negative result.

  • Availability/access: For SIPS, blood tests can be done in any community laboratory. For IPS, the blood tests are done in any community lab and the NT ultrasound is available at multiple NT ultrasound sites throughout the province. For FTS, there are a limited number of private clinics which offer this service (Victoria, Burnaby, Kelowna). Visit our NIPT page for more information about availability of testing in BC.

  • Timing of results: Results for SIPS and IPS are available 10 days after the second blood test which could be as early as the end of the 16th week of pregnancy. Results of FTS and NIPT could be available as early as the 11th week of pregnancy depending on when the screening test is done.

  • Cost: SIPS and IPS are covered by BC Health Care (MSP), so there is no cost for the patient. The cost of private FTS varies between centres and is approximately $500. The cost of NIPT varies.


 

Since most women who have screening (of any type) will have a screen negative result, getting the results earlier may mean earlier peace of mind. 

Regardless of the screening test chosen, all women with a screen positive result will be offered a diagnostic test to find out for sure whether the pregnancy is affected. This is a very important step before making a decision about the pregnancy. When NIPT is used as a first screen in women of all ages, a positive NIPT test result indicating a risk of Down syndrome greater than 99% can still be a false positive result. In fact, if 10 young women having NIPT as their only screen have a positive NIPT result with a risk of Down syndrome greater than 99%, only 6-8 of them will have a baby with Down syndrome. The other women have healthy babies and their test result was actually a false positive.

Women who screen positive by NIPT should be offered genetic counselling to discuss their options for diagnostic testing. One option is chorionic villi sampling (CVS), which occurs between 11 and 13 weeks) and is only available at BC Women’s Hospital & Health Centre. The other option is an amniocentesis, which can be done as early as 14 weeks in women at very high risk of a chromosomal abnormality. The amniocentesis is considered the option of choice given the cells tested come from the fetus. However, factors such as gestational age at the time of the positive result, ultrasound findings, chromosome involved, and maternal age must be considered when deciding which procedure to have.

Women who screen positive by IPS or SIPS would be offered an amniocentesis, which normally occurs anytime after 15 weeks. Amniocentesis is available at many hospitals around the province.

Both CVS and amniocentesis are covered by MSP for women who screen positive. Results from either a CVS or amniocentesis will tell whether the baby has a chromosome abnormality such as Down syndrome. For women having an amniocentesis because of an increased risk of Down syndrome or trisomy 18, if a rapid lab test is done, results are available in three days. If an analysis of all chromosomes is done, results take about two weeks. If the pregnancy is found to carry a chromosome abnormality, a woman has the option to continue or end the pregnancy.


 

There is no benefit in doing more than one screening test. In fact, it’s a disadvantage to have results from more than one screening test as it increases your chance of having a false positive test result. SIPS/IPS measures different markers than FTS to calculate the risk of Down syndrome. NIPT studies the DNA coming from the placenta into the maternal blood and uses different technology to analyze the results. So having results from different screens can be confusing and misleading to you and your health care provider. 

The publicly available screening tests (IPS, SIPS, Quad) screen for open neural tube defects (such as spina bifida). However, if you chose FTS or NIPT as a screen, open neural tube defects will be looked for at the time of your detailed ultrasound (19-20 weeks gestation). 

It’s important to talk to your health care provider and decide which route (public or private) you wish to take in your pregnancy.


 
SOURCE: Provincially Funded and Privately Paid Screening Tests ( )
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