The practice of ordering routine blood tests for patients attending hospital regardless of clinical need is wasteful and potentially damaging.
Repetitive inpatient blood testing occurs frequently and is associated with adverse consequences for the hospitalized patient such as iatrogenic anemia, and pain. A Canadian study showed significant hemoglobin reductions as a result of phlebotomy. Given that anemia in hospital patients is associated with increased length of stay, readmission rates and transfusion requirements, reducing unnecessary testing may improve outcomes. Studies support the safe reduction of repetitive laboratory testing without negative effects on adverse events, readmission rates, critical care utilization or mortality. Laboratory reduction interventions have also reported significant cost savings. (from https://choosingwiselycanada.org/internal-medicine/ )
Attali M, et al. A cost-effective method for reducing the volume of laboratory tests in a university-associated teaching hospital. Mt Sinai J Med. 2006 Sep;73(5):787-94. PMID: 17008940.
Lin RJ, et al. Anemia in general medical inpatients prolongs length of stay and increases 30-day unplanned readmission rate. South Med J. 2013 May;106(5):316-20. PMID: 23644640.
Smoller BR, et al. Phlebotomy for diagnostic laboratory tests in adults. Pattern of use and effect on transfusion requirements. N Engl J Med. 1986 May 8;314(19):1233-5. PMID: 3702919.
Thavendiranathan P, et al. Do blood tests cause anemia in hospitalized patients? The effect of diagnostic phlebotomy on hemoglobin and hematocrit levels. J Gen Intern Med. 2005 Jun;20(6):520-4. PMID: 15987327.