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Source file: CSR Guide_VanGenes NIPPT – Special Circumstances Support.pdf
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CSR Guide_VanGenes NIPPT - Special Circumstances Support
Internal Q&A Reference
The VanGenes Non-Invasive Prenatal Paternity Test (NIPPT) can support several special pregnancy
scenarios, including twin pregnancies, IVF pregnancies, and surrogacy cases.
It is important that clients inform us of the pregnancy circumstances before testing begins, as
special sample requirements may apply, and additional costs may apply depending on the case.
- Twin Pregnancies
Q: Can a prenatal paternity test be performed if the mother is pregnant with twins?
Yes. Prenatal paternity testing can be performed for twin pregnancies.
The laboratory supports testing in both:
- Identical twin pregnancies
- Fraternal twin pregnancies
However, the testing approach differs depending on the type of twin pregnancy.
Q: What is required for identical twins?
For identical twin pregnancies, standard NIPPT sample requirements apply.
This means:
- Maternal blood sample
- Alleged father DNA sample (buccal swabs)
No additional samples are required.
Q: What is required for fraternal twins?
If the pregnancy involves fraternal twins, the laboratory strongly recommends submitting samples
from all possible alleged fathers.
This is because each fetus may have a different biological father.
Q: What happens if only one alleged father is tested in a fraternal twin pregnancy?
If only one alleged father sample is provided:
- A supportive result means there is a very low probability that the other twin has a different
father.
- A not supportive result means the alleged father is not the biological father of either fetus.
For this reason, the laboratory recommends submitting all alleged father samples whenever
possible.
- IVF Pregnancy (Mother's Own Pregnancy)
Q: Can the prenatal paternity test be performed if the pregnancy resulted from IVF?
Yes.
Prenatal paternity testing can be performed for IVF pregnancies when the mother is carrying her
own pregnancy.
There are two testing options.
Q: What are the testing options for IVF pregnancies?
Option 1
Test between father and fetus
- Standard sample requirements apply.
Option 2
Test between both parents and fetus
Requirements:
- Pregnancy must be more than 10 weeks gestation.
However, the laboratory notes that there is a possibility that the maternal relationship result cannot
be issued.
Q: Why might the maternal relationship result not be issued?
In some IVF cases, the laboratory may not be able to issue a maternal relationship result due to
technical limitations in the analysis.
CSR should inform clients that while testing can be performed, maternal confirmation may not
always be possible.
- Surrogacy Pregnancies
Q: Can a prenatal paternity test be performed for a surrogacy pregnancy?
Yes.
However, surrogacy cases have additional requirements, and the laboratory must be informed that
the pregnancy involves surrogacy before testing begins.
Q: What are the testing options for surrogacy cases?
Option 1
Test between father and fetus
Requirements:
- Pregnancy must be more than 10 weeks gestation
- Surrogacy must be declared at the time of submission
Option 2
Test between father and egg donor
Requirements:
- Pregnancy must be more than 10 weeks gestation
- Maternal peripheral blood sample
- Egg donor DNA sample
- Alleged father DNA sample
- Important Surrogacy Result Handling (Internal Guidance)
In surrogacy-related cases, the laboratory focuses on the biological relationship between the
declared egg donor and/or sperm donor and the fetus.
If the result indicates a negative relationship, the laboratory may communicate this result verbally
only and may not issue a written report.
This approach is used to reduce the risk of disputes involving surrogacy agencies and donor
declarations.
CSR should not promise that a written report will always be issued in surrogacy cases.
If a client asks about this situation, the case should be escalated to management before providing
a definitive response.
- Minimum Pregnancy Requirements
Q: When can samples be collected for these special cases?
For certain special circumstances, the pregnancy must be at least 10 weeks gestation before
sample collection.
This requirement applies to:
- IVF testing involving both parents
- Surrogacy cases
Q: What must the client tell us before ordering?
Clients must inform us if the pregnancy involves:
- Twins
- IVF
- Surrogacy
This allows the correct testing option and sample requirements to be applied.
Failure to disclose this information may delay testing.
- Situations Where Testing Cannot Be Performed
Q: Are there any situations where the prenatal paternity test cannot be performed?
Yes.
The prenatal paternity test cannot be performed when:
- The alleged fathers are close blood relatives
- The case involves incest
- Vanishing Twin Syndrome (VTS)
Q: Can the test be performed if there was a vanishing twin?
Yes.
If one embryo disappears before 8 weeks, sample collection can be performed after an interval of
8 weeks.
This waiting period allows remaining fetal DNA to stabilise before testing.
CSR Escalation Guidance
CSR should escalate the case to management if:
- The pregnancy involves surrogacy with complex donor arrangements
- A client requests written confirmation of negative surrogacy results
- There is uncertainty about egg donor involvement
- The case involves multiple alleged fathers in twin pregnancies