Prenatal-Perinatal Diagnosis
Rhesus D non-invasive prenatal testing (RHD NIPT)
The RHD NIPT is a screening test that looks at your baby's DNA that is found in your blood. It is specifically recommended for all pregnant patients with Rhesus negative blood type to determine if your baby is likely to have Rhesus positive or negative blood type. This is a separate test to the non-invasive prenatal testing (NIPT) that screens for chromosomal abnormalities or other genetic conditions.
Learn more about the RHD NIPT and download a request form.
Prenatal testing
PathWest offers a comprehensive range of prenatal diagnostic testing:
Test Name |
Turnaround Time** |
| Rapid aneuploidy testing by QF-PCR | 3 days |
| Cytogenetics (karyotyping, chromosomal microarray) | 10-15 days |
| Known familial or targeted variant analysis* (advance notification of test request is required) |
10-15 days |
| Untargeted single gene or gene panel analysis* | 3-6 weeks |
*Subject to test availability. Please contact the laboratory to confirm testing can be offered.
** >90% of prenatal requests are reported within the specified turnaround time.
Prenatal testing for ongoing pregnancies requires a specific request form for appropriate testing, and maternal blood sample to be sent for maternal cell contamination studies and confirmation of identity of the prenatal sample.
Pregnancy loss testing
All requests received by PathWest for chromosomal/cytogenetic analysis of fresh products of conception or fetal tissue are analysed by chromosomal microarray. This testing is most relevant for investigation of couples with recurrent pregnancy loss or where fetal structural anomalies have been identified.
Prior to sending a test request, it is important that couples/individuals are counselled by the requesting clinician regarding the benefits, limitations and complexities of microarray. To help guide this conversation and inform patient consent, resources are available from the Clinician Resources page.
Non-invasive prenatal testing for chromosome anomalies (NIPT for chromosomal anomalies)
Please note, NIPT for chromosomal anomalies is different to the RHD NIPT offered by PathWest.
External provider NIPT for chromosomal anomalies can be accessed at any PathWest collection site. There are currently many private NIPT service providers with alternative products aimed at the detection of chromosomal anomalies.
While the various NIPT services overlap for detection of the main targeted chromosomal abnormalities, there may be differences in sample kits, technological approaches, test accuracy within specific clinical scenarios, range of detected abnormalities, turnaround time and cost.
Due to specific collection container requirements, sample collection can only be arranged for external NIPT providers listed on the PathWest Test Directory.
Please note, sample collection and processing are greatly facilitated if the request form specific to the service provider is appropriately completed and payment is confirmed.
Collection kits will be available in stock at PathWest sites for NIPT brands listed on the PathWest Test Directory. Please contact your local PathWest collection centre to ask about kit availability.
Download a Harmony or Percept referral form for a NIPT from an external provider.
Reproductive carrier screening
External provider carrier screenings that have an associated Medicare rebate (items 73451 and 73452) can be accessed at any PathWest collection centre (as a send-away test). This test informs reproductive decisions in relation to the following common genetic recessive conditions:
- Cystic Fibrosis
- Spinal Muscular Atrophy
- Fragile X syndrome.
Test requirements are outlined on the PathWest Test Directory.
Carrier screening for other rare recessive conditions - known as expanded RCS - are generally associated with an out-of-pocket expense. Private service providers offer a range of expanded RCS options for individuals and couples, varying in the number of genes assessed, testing for targeted population backgrounds, and costs. PathWest provides expanded RCS exclusively for couples who have a higher prior risk than the general population for having children with a rare recessive condition. This service is only available through referrals from Genetic Health WA.