GYNEC EXPERT

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What is fetal fraction cut-off

for NextGen NIPT?

What are the limitations

for NIPT?

There is a minor possibility for false positive

or false negative results. This may be

caused by technical and/or biological

limitations, including but not limited to:

Contraindications for NIPT?

Fetal fraction is the amount of fetal cell

free DNA obtained from the maternal

blood. The fetal fraction cut off for

NextGen NIPT is 3.5 %

Fetal fraction less than 3.5 % leads to

inconclusive reports, in such cases

repeat sample testing should be

considered.

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other types of Placental Mosaicism

Maternal constitutional or somatic

chromosomal abnormalities

Residual cf-DNA from a vanished twin or

other rare molecular events 4

Cancer

Chromosomal

abnormality

Organ transplant,

stem cell therapy/

immunotherapy

Multiple pregnancy

greater than twins

If parents have a

known family history of

single gene disorders2

Patients on

Anticoagulants and

Cytotoxic drugs

What should be done after

getting a high risk/ low risk

report on maternal screening?

The patient should

be given an option

for undergoing

��NIPT (which is

more sensitive

than maternal

screening but, a

screening test)

��Diagnostic tests

like Karyotyping,

FISH or Microarray

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samples.

NIPT can be

prescribed in

cases of:

1. Increased

maternal age.

2. Previous history

of child with

chromosomal

abnormalities.

3. USG

abnormalities.

High risk in

maternal

screening

report

Low risk in

maternal

screening

report

Intermediate

risk* in 1T

maternal

screening report

(1:251-1:1000)

*For Trisomy 21 only

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