What is Noninvasive Prenatal Testing (NIPT) ?

Introduction:

Non-invasive prenatal testing (NIPT) is a revolutionary advancement in prenatal screening which can
detect circulating genetic material (DNA) from the foetus in peripheral blood of mother via simple
routine blood test.

Process of NIPT Testing:

The NIPT test screens a maternal blood sample for chromosome aneuploidy in fetal DNA using the following
methodology:
(1) Extraction of cell free fetal DNA from the maternal blood sample
(2) High throughput sequencing of the extracted cell free fetal DNA
(3) Calculation of molecular mass of fetal DNA in all chromosomes

Why We Use NIPT?

NIPT is a non-invasive, low-risk, highly sensitive and specific method for prenatal examination

This test is used to detect following syndrome:

·       Trisomy 13 (Patau Syndrome)

·       Trisomy 18 (Edwards Syndrome)

·       Trisomy 21 (Down Syndrome)

Sensitivity and Specificity of NIPT:

Sensitivity and Specificity of NIPT is over 99%

To validate the sensitivity and specificity of NIPT we sequenced and analyzed 10,690 plasma samples from pregnant women. The aneuploidy samples are validated by MPLA or karyotyping and the wild type results are validated by karyotyping or tracked until birth.

	Sensitivity	Specificity	PPV (Positive Predictive Value
T21	98.5%	99.9%	94.4%
T18	99.9%	99.9%	92.8%
T13	99.9%	99.9%	91.8%
Sex Chromosome	90.0%	99.9%	75.0%

Reporting Time:

The NIPT report is available within 10 working days

Features of this Test:

NIPT technologies have been validated in singleton pregnancies at high risk for trisomy 21 due to:
• Advanced maternal age ≥ 35 at delivery
• Abnormal Ultrasound findings- High NT/absent nasal bone
• Suspicious serum markers for Trisomy 13.18,21
• Personal or family history of aneuploidy.
• A previous pregnancy with a chromosomal abnormality
• Received IVF treatment / Donor egg

Advantages of NIPT over other Maternal Markers:

• Highly accurate: The NIPT test uses the Next-generation sequencing technology to reach a
detection rate of >99%
• Simple: The NIPT test only requires 10ml of maternal peripheral blood.
• Risk-free: Testing peripheral maternal blood prevents intrauterine infection and the risk of
miscarriage
• Early-test: The NIPT test allows testing as early as the tenth week of gestation

How to Collect Samle of NIPT:

For a NIPT 10 ml peripheral maternal blood is required. Specimen collection is done in special streck tube

Limitation of NIPT:

           This test has limitations on the detection of chromosomal structural abnormality for gene dosage changes due to micro­deletions, chromosome re­arrangements, translocations, inversions, unbalanced translocations, uniparental disomy, and chromosome mosaicism. Screening for these abnormalities has been excluded from the NIPT test. As such, given a negative test result, it cannot be claimed that a fetus is free from a genetic disease.

           The accuracy and quality of the test may be affected by improper blood sample collection, storage and transportation. The test is not intended for use in women with chromosome aneuploidy, multiple gestation, or women with a gestation period of less than 10 weeks.

            This test is not suitable for:
1.​ Patients with dizygotic multiple gestation.
2. Patients with diagnostics results that have revealed chromosomal aneuploidy.