Genetic testing, sometimes called molecular or genomic testing, examines your DNA to identify changes (variants) in genes or chromosomes. Your genes, made of DNA and inside every one of your cells, are like instruction manuals that tell your body how to make all the things it needs to keep you healthy. Finding changes in your genes can help diagnose a health condition, determine your risk of developing one, or show whether you could pass a genetic condition to a child.
Some tests analyse a single gene, while others examine many genes at once. Genetics refers to the study of individual genes, while genomics looks at all of a person’s genes together (the genome) and how they interact with each other and the environment.
Genetic and genomic testing are rapidly expanding as research identifies new variants and clarifies how they contribute to disease. These tests are increasingly used in routine medical care across reproductive health, cancer, inherited disorders, infectious diseases and personalised medicine.
When are you likely to encounter genetic testing?
Before pregnancy
Reproductive carrier screening (RCS) can identify whether you and your partner carry genetic variants that could cause a serious inherited condition in your child. Modern panels test for hundreds of genetic conditions.
During pregnancy
Non invasive prenatal testing (NIPT) looks at fragments of foetal DNA circulating in the mother’s blood to assess the risk of chromosomal conditions such as Down syndrome. NIPT is a screening test, not a diagnostic test, and abnormal results require confirmatory testing.
The same technology is used in “liquid biopsy” testing to detect DNA shed by cancer cells, which may allow earlier diagnosis or monitoring of cancer.
Cancer diagnosis and treatment
Tumour genomic testing identifies mutations that drive cancer growth. These results help determine the cancer subtype, suitability for targeted therapies, likelihood of response to immunotherapy and prognosis and treatment planning.
This approach is known as precision oncology.
Inherited conditions
Genetic testing can confirm or rule out if a pathogenic variant (mutation) has been inherited for disorders such as inherited risks for developing cancer, heart disease, or other conditions.
Testing may also be offered to family members to clarify their risk.
Medication response (pharmacogenomics)
Genetic variants can influence how quickly or slowly you break down certain medications.
This information can guide safer prescribing for drugs such as antidepressants, anticoagulants, pain medicines and some cancer therapies.
Infectious diseases
Genetic testing is widely used to detect viruses and bacteria, including COVID 19, influenza and many others. DNA and RNA sequencing can also identify antimicrobial resistance genes, helping guide appropriate antibiotic treatment.
For a glossary that explains common genetics terms that you may see in test results or in health information, see here.
Genetic tests in the Pathology Tests Explained library
You’ll find many genetic tests in the Pathology Tests Explained library. The table below lists some of the more commonly requested tests and the conditions to which they relate.
| Genetic test | Condition(s) |
| ALK Mutation | Non-small cell lung cancer |
| Apo E genotyping | Lipoprotein and cholesterol disorders Late onset Alzheimer's |
| B-cell immunoglobulin gene rearrangements | B-cell lymphoma |
| BCR- ABL1 | Chronic myelogenous leukaemia (CML) Acute lymphoblastic leukaemia (ALL) |
| CF gene mutation testing | Cystic fibrosis |
| Chromosome studies | Chromosome abnormalities linked to genetic disorders and some blood and lymphoid disorders |
| EGFR mutation testing | Non-small cell cancer |
| Factor V Leiden & PT 20210 | Deep venous thrombosis (DVT) and venous thromboembolism (VTE) |
| Familial hypercholesterolaemia (FH) genetic testing | Inherited high levels of LDL cholesterol |
| FMR1 mutations | Fragile X Syndrome |
| Genome-wide microarray testing | Developmental problems in children |
| HER2/neu | Breast cancer |
| HFE mutations | Haemochromatosis |
| HIV genotypic resistance | Guiding antiviral therapy for HIV |
| HLA testing | Organ or bone marrow transplants |
| Inherited cancer risk - bowel and endometrial cancer | Colorectal, endometrial and related cancers, including Lynch syndrome |
| JAK2 mutation | Bone marrow disorders including polycythaemia vera, essential thrombocythaemia and primary myelofibrosis |
| Microsatellite instability | Colorectal cancer |
| MPL mutation | Myeloproliferative neoplasms (MPNs) |
| MTHFR mutation | Follow-up of high blood homocysteine; family history of premature cardiovascular disease or clots |
| NIPT | Down syndrome and other chromosomal disorders |
| Reproductive Carrier Screening | Inherited conditions that could be passed to a child |
| Pharmacogenomic tests | Choice of medication and dosage |
| PSEN1 | Early onset Alzheimer's or dementia |
| Somatic tumour gene testing | Cancer |
| T-cell receptor gene rearrangements | T-cell lymphoma |
| TPMT (Thiopurine methyltransferase) | immune suppressant medications |
| VHL Gene Mutation | Von Hippel-Lindau syndrome |
| Whole genome or whole exome testing for childhood syndromes | Developmental problems in children |
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