CF Gene Mutation Testing

Other names: Cystic Fibrosis (CF) Genotyping; CF Gene Mutation Panel; CF DNA analysis; Molecular Genetic Testing

The CF gene mutation test is used to test for abnormalities with the CFTR gene. The test is primarily used to test for cystic fibrosis, a serious inherited condition, which affects the whole body but has a particularly severe effect on the lungs. Cystic fibrosis is caused by mutations with both alleles of the chromosome 7 gene. If one allele is abnormal, the patient may be classed as a transporter and have the potential to pass the condition onto their child.

When is the test used?

The CF gene mutation test is used to diagnose a patient or check to see if a patient is a carrier for the disease. The test may be ordered to discount cystic fibrosis in the event that a patient displays symptoms associated with cystic fibrosis; possible symptoms include:

  • Persistent lung infections
  • Salty sweat
  • Chronic diarrhoea
  • Vitamin deficiency
  • Malnutrition
  • Strong, foul-smelling stools
  • Wheezing and breathing difficulties
  • Bulky stools

The CF gene mutation test could also be done if a patient has tested positive for the sweat chloride or IRT test.

How is the test performed?

The test is done by collecting and analysing a sample of blood; the blood is taken from an arm vein using a needle. Once the sample has been collected, it will be bottled, labelled and sent away to the laboratory.

In infants, the blood sample is taken from the heel; the heel is pricked and a small sample is collected and then sent away for analysis.

What do the test results show?

If the test returns positive and shows two gene mutations, the patient will be diagnosed with cystic fibrosis. The test cannot determine the severity of the patient’s symptoms; some patient will have more severe symptoms than others.

If the test is negative with the patient displaying no symptoms, it is very unlikely that the patient will have cystic fibrosis; it is also unlikely that they are a carrier.

If the test detects a single gene mutation and the patient has no symptoms, it is likely that the patient is a carrier for cystic fibrosis; this means that they may pass the condition onto their children but will not suffer from the condition themselves.

If the test returns negative but the patient has symptoms of cystic fibrosis, this may indicate that the patient has a rare form of the disease and the doctor will order further tests, including the sweat chloride test, genetic tests and organ function tests.

Early diagnosis of cystic fibrosis will help to improve the patient’s quality of life; the earlier they start treatment, the more effective the treatment.

Specific Blood Tests

Blood Test Guide

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