Residual Risk Calculator: Carrier Testing Results

About this carrier risk calculator

This genetic risk calculator looks up carrier risk for autosomal recessive and X-linked conditions. Enter a gene (for example CFTR, HBB or SMN1) or a disorder (for example cystic fibrosis, sickle cell disease or spinal muscular atrophy) to see the population carrier frequency, the detection rate of the test, and the carrier probability after a negative genetic test.

Residual risk of an affected child

Each result also shows the residual risk of an affected child in four partner scenarios: one partner tests negative and the other’s carrier status is unknown; both partners test negative; one partner tests negative and the other is a known carrier; and both partners are known carriers. Changing the detection rate recalculates both the post-test carrier risk and the residual risk.

Carrier frequencies are general-population estimates and are not adjusted for ancestry or family history. Use the result alongside a clinical assessment, not in place of genetic counselling.