Despite efforts by test maker Grail to highlight outcomes the company considers positive, some experts are warning against using the Galleri test and others like it.

A closely watched clinical trial in Britain that screened blood for early detection of cancer did not show a reduction in diagnoses at later stages of the disease.

A blood test designed to find cancer early did not work as hoped in a major new study, according to the company that makes it. The test, called Galleri, failed to lower the number of people diagnosed ...