I feel completely well — why would I get carrier screening?

Most carriers have no symptoms and are perfectly healthy. Carrier screening is not about your own health; it tells you whether you could pass a recessive condition to a child if your partner carries the same one.

If I am a carrier, does that mean I have the disease?

No. For recessive conditions, a carrier has one altered gene copy and one normal copy and is generally unaffected. A child is usually only affected if they inherit an altered copy from both parents.

We are both carriers of the same condition — will our child definitely be affected?

No. For a typical autosomal recessive condition the chance is generally about 1 in 4 (25%) in each pregnancy — meaning most pregnancies are unaffected — but this is a probability, not a certainty. A genetic counsellor can explain your specific situation.

When should we do it?

Ideally before pregnancy, so you have time and the widest range of options. It can still be done in early pregnancy.

If my result is “negative,” is there zero risk?

A negative result lowers the risk but cannot rule it out completely, because a test checks only certain genes and variants. Your clinician can explain what your particular test did and did not cover.

Carrier Screening in Singapore: Planning a Family

Written & reviewed by the BestDoctors.sg editorial team · Last updated 25 Aug 2026 · General information, not medical advice

Carrier screening is a test (usually blood or saliva) that tells a healthy person whether they carry a gene change for a recessive condition that could be passed to their children. Being a carrier means you have one working copy and one altered copy of a gene — for recessive conditions, carriers are typically healthy with no symptoms. It matters most when both partners carry the same recessive condition. In Singapore, thalassaemia is the most relevant example, and screening is ideally done before or early in pregnancy.

Worried about your child’s health or development?

Message our care team on WhatsApp. Tell us what’s going on and we’ll help you find the right paediatrician — free, with no obligation.

Chat with our care team on WhatsApp

Not sure who to see? Find the right specialist →

In a medical emergency, or for severe or sudden symptoms such as breathing difficulty, chest pain, fainting or stroke signs, call 995 immediately.

Being a carrier is not having the disease and usually causes no symptoms. A “negative” screen lowers but does not completely remove risk, because a panel checks only specified genes. Decisions are personal and best made with genetic counselling.

What it is

Carrier screening finds out whether you carry a gene change for a recessive condition that could be passed on. For an autosomal recessive condition, a child is generally affected only if they inherit an altered copy from both parents, so a carrier — with one altered and one working copy — is usually healthy. The information is mainly useful for reproductive planning rather than for your own health.

Why it matters

When both partners carry the same recessive condition, then for a typical autosomal recessive condition each pregnancy generally has about a 1-in-4 (25%) chance of an affected child, a 2-in-4 chance of an unaffected carrier child, and a 1-in-4 chance of a child who is neither — a probability, not a guarantee, meaning most such pregnancies are unaffected. If only one partner carries a given condition, their children are generally not at risk of being affected by it, though a child may be a carrier. X-linked conditions such as G6PD deficiency follow a different pattern.

Who it is for

Carrier screening is offered to people planning a pregnancy (ideally before conception) or in early pregnancy, to couples generally, to those with a family history of a genetic condition, and to people from ancestry groups where certain carrier conditions are more common. It is an option to inform choices, not a requirement, and framing is always neutral.

What it involves

Screening uses a blood or saliva sample from one or both partners. It ranges from targeted single-condition testing — for thalassaemia, this typically starts with a full blood count looking at red-cell size, with haemoglobin studies to confirm — to “expanded” panels covering many conditions at once. A common approach is sequential: test one partner first, and test the second partner in detail only if the first is found to be a carrier. This keeps testing proportionate, because the result that matters for a couple is whether both partners carry the same condition, not simply whether one of them is a carrier of something. Turnaround is usually a few days to a couple of weeks, and a genetic counsellor can help decide which conditions to include and how to interpret whatever comes back.

Conditions relevant in Singapore

Thalassaemia is highly relevant across Singapore’s Chinese, Malay and Indian populations, and carrier (trait) status is common; our dedicated thalassaemia guide covers it in detail. G6PD deficiency is also common locally and is screened for in newborns, and it is X-linked, so its inheritance differs from the 1-in-4 model. Other conditions sometimes included on panels are cystic fibrosis, spinal muscular atrophy and other haemoglobin disorders such as sickle cell disease. Because carrier frequencies differ between ancestry groups, the conditions worth including can depend partly on family background, and Singapore’s multi-ethnic population means thalassaemia in particular is a long-standing focus of preconception and antenatal screening here. Being told you carry a trait can feel worrying at first, but it is common, it does not affect your own health, and it simply gives you and your partner useful information for planning.

What results mean and their limits

“Carrier detected” means you carry one altered copy and are generally healthy; the significance is mainly for reproductive planning. “No variant detected” reduces but does not eliminate risk, because a panel tests only certain variants and rare ones can be missed. And a result on one partner is only fully informative once the other partner’s status for the same condition is known — which is why partner testing follows a positive result.

What couples can do and how to access it

If both partners carry the same condition, options to consider — neutrally, and with counselling — include partner testing to clarify risk, proceeding with a pregnancy informed and prepared, prenatal diagnosis, or other reproductive routes such as IVF with pre-implantation genetic testing, donor gametes or adoption; specifics and eligibility are discussed with a clinician, who presents the menu neutrally rather than steering you toward any one path. In Singapore, screening is accessed through a GP, obstetrician or antenatal and genetics services at hospitals such as KKH and NUH, with thalassaemia screening long established as part of routine care here. HealthHub and MOH offer general information.

Related genetics & genomic-health topics

Sources

MedlinePlus — Genetic testing (carrier testing): medlineplus.gov
NHS — Genetic and genomic testing: nhs.uk
Bestdoctors.sg — Thalassaemia in Singapore: Thalassaemia guide

General information only. This guide is general information about a genetics topic and is not a diagnosis, a genetic test result, or personalised medical advice. Genetic test results have implications for you and your blood relatives and should be interpreted with a doctor or genetic counsellor. A raised genetic risk is not a certainty, and a “normal” result does not remove all risk. Do not start, stop or change any medicine or make a medical decision based on a genetic test — including a direct-to-consumer test — without your doctor. Call 995 for any sudden, severe symptoms — such as chest pain, breathlessness or collapse, or a severe drug reaction with a spreading rash, blistering or peeling skin and fever.