Genetic testing
Also known as: DNA test, gene panel, genomic testing
Reading part or all of a person's DNA (from blood or saliva) or a tumour's DNA (from a biopsy) to find variants that cause disease, raise risk, or predict which drug will work. Modern sequencing panels test hundreds of genes at once.
- Abbreviations
- NGS, WGS
- Kind
- Genetic or molecular test
- Categories
- Genetic & molecular
- Specimen
- Venous blood, Saliva, Tissue
- Method
- DNA sequencing, PCR (including RT-PCR and qPCR), Karyotype, Chromosomal microarray
- Molecular scope
- the field in general
What it measures
| Measure | What it tells you |
|---|---|
| Diagnostic testing | Confirms a suspected inherited condition (cystic fibrosis, Huntington disease, familial hypercholesterolaemia). |
| Predictive testing | Finds high-risk variants before disease appears (BRCA1/2 for breast and ovarian cancer, Lynch syndrome for bowel cancer). |
| Tumour profiling | Mutations in the cancer itself (EGFR, ALK, KRAS in lung cancer) that match targeted drugs. |
| Pharmacogenomics | Variants that change how drugs are handled (DPYD before fluorouracil, HLA-B*57:01 before abacavir). |
Why it is ordered
- A family history of cancer at young ages or in several relatives
- A child with developmental problems or an unexplained syndrome
- Choosing targeted cancer treatment
- Planning a pregnancy in carriers of recessive conditions
- Sudden cardiac death in a young relative
How it is done
A blood or saliva sample after genetic counselling; results take weeks. Tumour testing uses the existing biopsy.
Preparation. Counselling before predictive tests, because results affect relatives and insurance in some countries.
Reading the result
| Finding | Usual meaning |
|---|---|
| Pathogenic variant found | Diagnosis confirmed or high risk established; cascade testing offered to relatives |
| Variant of uncertain significance | Cannot be interpreted yet; not used for clinical decisions |
| No variant found | Lowers but does not abolish risk; the test only reads the genes on the panel |
Reference ranges vary by laboratory, method, age, sex and clinical context; a result is read against the person, not a table.
Limitations
Most common diseases are polygenic and environmental, so a single gene test says little; incidental findings and implications for family members need careful counselling.
Catalogued concepts this page covers
Concepts of the master test taxonomy that resolve to this page; each links to its category.