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Extra blood tubes rarely used for testing

Extra blood tubes were used for additional testing at a rate of 7%, according to findings published in JAMA Internal Medicine.

Robert M. Humble, BS, MS, from the University of Iowa, and colleagues indicated that these extra tubes represent an example of wasteful practice that can be more harmful than beneficial.

"Clinical laboratories often receive extra blood tubes beyond what is needed for associated laboratory test orders," Humble and colleagues wrote. "Sometimes, this practice involves drawing tubes of every possible color (the 'rainbow') to allow for add-on testing at a later time. Despite the widespread use of extra tubes, we found virtually no peer-reviewed literature on this practice. There has been more focus on phlebotomy draw volumes and iatrogenic anemia from repeated laboratory testing."

Humble and colleagues conducted a retrospective analysis of the use of extra blood tubes at the University of Iowa Hospitals and Clinics between May 2009 and June 2015. The researchers used data extraction reports from the electronic medical record.

They found that 370,601 extra blood tubes were collected, with 23.7% from the ED, 30.2% from outpatient clinics and 46.1% from inpatient units. Testing was highest for lithium-heparin plasma separator tubes, which are used for clinical chemistry tests, and K₂-EDTA tubes, which are commonly used for hematology tests.

In addition, serum tubes were used for add-on resting for less than 0.4% of cases.

The researchers noted that several changes occurred during the study period which led to temporary decreases in extra tubes, such as a switch to paperless labeling and a collaboration between clinics.

"Excessive use of extra tubes may contribute to iatrogenic anemia, patient discomfort, and risk of biohazard exposure," Humble and colleagues concluded. "Extra tubes also consume phlebotomy and laboratory resources in the collection, processing, and disposal of specimens. Ongoing education and changes in the [electronic medical record] may help address the use of extra tubes. At our institution, electronic order sets underwent extensive review and specify extra tube collection only for situations or protocols likely to need these tubes for add-on orders. Future studies are needed to understand the clinical situations under which extra tube collection is most appropriate." – by Chelsea Frajerman Pardes

Disclosures: Krasowski has served as the principal investigator for clinical trials for Roche Diagnostics and Radiometer Inc. No other authors reported any other relevant financial disclosures.