Different types of next-generation sequencing

A focused panel examines selected genes, exome sequencing concentrates on protein-coding regions, and whole-genome sequencing surveys a much broader range of DNA. Some tests analyse RNA to show which genes are active or to detect abnormal gene fusions.

The widest test is not automatically the most useful. A targeted panel can provide deeper coverage of changes already linked to a particular cancer, while broader testing may reveal unexpected findings but can also produce uncertain results. Tumour sequencing looks for changes within cancer cells; inherited testing usually uses blood or saliva to look for changes present throughout the body.

The laboratory also chooses a sequencing method suited to the material. DNA, RNA, a fresh sample and preserved tissue have different technical requirements. Results therefore depend on sample quality, the regions the assay can reliably read and the way findings are interpreted.

Confirm whether the aim is to guide cancer treatment, refine a diagnosis, assess an inherited condition or support reproductive care. Ask which sample will be tested, whether normal tissue is needed for comparison and what kinds of changes the assay may miss.

Discuss how uncertain or incidental findings will be handled and whether genetic counselling is appropriate. Keep the report for future care because interpretation can change as laboratories update how they classify variants.

Arrange a review when a report identifies an inherited change, an uncertain variant or a result that could alter treatment. A negative result does not exclude every genetic change, so persistent clinical concerns still need assessment in context.

Which sequencing approach matches my clinical question? Will this test examine tumour changes, inherited changes or both? How could the result affect my care, and who will explain uncertain findings?