Genetic Carrier Screening

Causes & Risk Factors

Carrier screening is considered based on background risk factors rather than any current symptom, since carriers are typically healthy:

•  Family history of a known inherited genetic condition

•  Ethnic or population background associated with a higher carrier frequency for specific conditions

•  Consanguinity (blood relationship between partners), which increases the chance of both partners carrying the same recessive variant

•  A partner already known to be a carrier of a specific condition

•  Personal preference for reproductive planning, even without a specific known risk factor

Symptoms & When to Test

By definition, carriers of a recessive genetic condition are typically asymptomatic — this is precisely why screening, rather than symptom-based testing, is necessary to identify carrier status.

•  No symptoms are expected in a carrier of a single copy of a recessive condition

•  A family member affected by a genetic condition (not the person being screened) is often what prompts screening

•  Some panels also screen for conditions with more variable inheritance patterns, based on the specific panel selected

When Should You Consider Testing?

Carrier screening is ideally performed before conception, allowing couples the most time to understand results and consider options. It can also be performed during early pregnancy, though this narrows the window for some downstream decisions.

Why Tests Are Combined

Carrier screening is typically performed as a panel covering multiple conditions simultaneously — such as thalassemia and other hemoglobinopathies, cystic fibrosis, and spinal muscular atrophy — because testing for these conditions together, rather than one at a time, is more efficient and covers the conditions most relevant to reproductive risk in a single sample.

The clinical significance of a result depends on both partners' status: a single carrier generally faces no personal health risk, but if both partners carry a pathogenic variant for the same recessive condition, the risk to future pregnancies increases substantially — which is why partner testing is often recommended once one partner screens positive.

Genetic counselling is an important companion to carrier screening, helping couples understand what a positive result does and does not mean, and what reproductive options may be relevant.

Tests Available at NPL

Most reproductive hormone and genetic tests do not require fasting. However, some tests have specific timing requirements (such as a particular day of the menstrual cycle), and if other tests are ordered at the same time, fasting may be required for those investigations. Please follow the preparation and timing instructions provided by your doctor or NPL.

Home Sample Collection

NPL offers convenient home sample collection for Genetic Carrier Screening blood tests, so you don't need to visit a lab in person.

→ Book your test online, via the NPL app, or by calling +977 1 5970147 and select a convenient time slot for home sample collection.

→ A certified and experienced NPL phlebotomist visits your home at the scheduled time, following strict hygiene and safety protocols.

→ Your sample is transported under controlled, monitored conditions to NPL's NABL ACCREDITED UNDER ISO 15189:2022 laboratory for processing.

→ Your digital report is delivered securely to your phone or email, along with access to download and share it as needed.

When to See a Doctor

•  Planning conception, particularly with a family history of a genetic condition

•  Positive carrier result — partner testing and genetic counselling are recommended

•  Consanguineous relationship (blood relatives) with a partner

•  Ethnic background associated with a higher carrier frequency for a specific condition