Excessive Phlebotomy in Cardiac Surgical Care Leads to Anemia

Laboratory testing among patients undergoing cardiac surgery can lead to excessive bloodletting, which can increase the risk of developing hospital-acquired anemia and the need for blood transfusion.

Health care providers are seldom aware of the frequency and volume of phlebotomy for laboratory testing, bloodletting that often leads to nosocomial anemia. The frequency of laboratory testing in patients undergoing cardiac surgery, and the cumulative phlebotomy volume from time of initial surgical consultation to hospital discharge has been investigated.


Medical teams at the Cleveland Clinic (Cleveland, OH, USA) examined every laboratory test from 1,894 patients who underwent cardiac surgery from January to June 2012. The number and type of blood tests performed were recorded from the time patients met their surgeons until hospital discharge. The scientists then tallied up the total amount of blood taken from each patient. Phlebotomy volume was estimated separately for the intensive care unit (ICU), hospital floors, and cumulatively.

A total of 221,498 laboratory tests were performed, averaging 115 tests per patient. The most frequently performed tests were 88,068 blood gas analyses, 39,535 coagulation tests, 30,421 complete blood counts, and 29,374 metabolic panels. Phlebotomy volume differed between ICU and hospital floors, with median volumes of 332 mL and 118 mL, respectively. Cumulative median volume for the entire hospital stay was 454 mL. More complex procedures were associated with higher overall phlebotomy volume than isolated procedures. Foe combined coronary artery bypass grafting (CABG) and valve procedure, the median volume was 653 mL versus 448 mL for isolated CABG and 338 mL for isolated valve procedures.

Colleen G. Koch, MD, MS, MBA, the lead author of the study said, “We were astonished by the amount of blood taken from our patients for laboratory testing. Total phlebotomy volumes approached one to two units of red blood cells, which is roughly equivalent to one to two cans of carbonated beverage. Patients should feel empowered to ask their doctors whether a specific test is necessary, such as: What is the indication for the test? Will it change my care? And if so, do you need to do it every day? They should inquire whether smaller volume test tubes could be used for the tests that are deemed necessary. Every attempt should be made to conserve the patient's own blood, every drop of blood counts.” The study was published in the March 2015 issue of the journal the Annals of Thoracic Surgery.

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