The blood test that measures prostate specific antigen (PSA) to detect prostate cancer often produces false positive results and should be repeated at least once before an invasive biopsy is performed, a new study says.

“We recommend having the findings confirmed by repeating the test after waiting at least six weeks,” said Dr James Eastham, a surgeon in the department of urology at the Memorial Sloan-Kettering Cancer Center in New York and lead author of the study.

“Even if the repeat test shows an elevated level, prostate cancer will only be discovered in about one quarter of men who undergo biopsy… A single, elevated PSA level does not automatically warrant a prostate biopsy,” …