Avoid ordering tumor markers, particularly CEA, CA-125, HE4, AFP, and CA19-9, unless there is a known cancer diagnosis, a specific suspicion of a particular cancer type, or a strong underlying predisposition Avoid ordering vitamin D tests for individuals without an increased risk of vitamin D deficiency Avoid measuring testosterone in men without symptoms or signs of testicular failure Avoid routinely ordering free T3 and free T4 when investigating thyroid disease or monitoring patients with primary hypothyroidism. TSH is sufficient in most cases Avoid testing for occult blood in stool for indications other than suspected colorectal cancer. Quantitative immunochemical tests (iFOBT) should replace chemical tests Avoid repeated blood tests in clinically stable patients