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Singing the Blues for Blue Top Tubes

December 30, 2021
Mark A. Crowther, MD
Chair of the Department of Medicine at McMaster University in Hamilton, Ontario, Canada and Treasurer of the American Society of Hematology
Steven L. Allen, MD
Associate Chief of the Division of Hematology at Northwell Health Cancer Institute and System Head, Benign Hematology of the Northwell Health System in Lake Success, New York

Here, Mark A. Crowther, MD, and Steven L. Allen, MD, discuss the recent shortages of blue top tubes and how hematologists can "choose wisely" to help manage the crisis.


You are a typical busy hematologist scrambling to stay on schedule while still taking the time to formulate a thoughtful plan for the patient in front of you. Perhaps it is a clotting conundrum. You think to yourself, What diagnostic tests are needed? You may even subconsciously recall what color top tubes will be drawn, but have you ever worried whether your lab has the necessary tubes? Or even given a thought to the possibility that global events might impact your ability to evaluate or care for your patients?

That almost unimaginable development has come to pass. In late May, multiple laboratories began to announce shortages of 3.2% sodium citrate blue top tubes – the tubes that enable most of our basic coagulation tests to be performed. This shortage is expected to persist through 2021. In an illustration of the severity of this issue, a major university-owned lab sent out an alert on May 14 that it had only a 14-day supply of blue tops left. How could this happen?

A perfect storm is the explanation, with COVID-19 at its core. The coagulopathies and thrombotic complications associated with COVID-19 infection markedly increased the demand for coagulation testing. This occurred in the setting of a simultaneous worldwide shortage of sodium citrate, the anticoagulant in blue top tubes. The increased demand exceeded both the available supply and production capacity. The issue has been further exacerbated by a COVID-19—associated disruption of supply chains, a shortage of plastics, and a product recall. There were even unsubstantiated rumors that thrombosis of the Suez Canal by that grounded container ship (talk about clotting problems!) had contributed to the shortage.

What can be done to mitigate this potential crisis? For one thing: choose wisely! This current shortage emphasizes the importance and relevance of the 2013 Choosing Wisely® recommendations, an initiative of the ABIM Foundation, from the American Society of Hematology (ASH) and the American Society for Clinical Pathology (ASCP). ASH recommended, "Don't test for thrombophilia in adult patients with venous thromboembolism occurring in the setting of major transient risk factors (surgery, trauma, or prolonged immobility)."1 ASCP recommended, "Avoid routine preoperative testing for low-risk surgeries without a clinical indication."2 This latter recommendation reinforces the need to avoid unneeded prothrombin time/international normalized ratio (PT/INR) and partial thromboplastin time testing. These tests are often ordered at admission and in the perioperative setting – yet almost never actually inform care.

A timely addition to the Choosing Wisely campaign recently published by a joint task force from ASH and the American Society of Pediatric Hematology/Oncology echoes these recommendations for the pediatric population. First among their five recommendations is to avoid routine preoperative hemostatic testing in an otherwise healthy child without personal or family history of bleeding. Also included was the suggestion to avoid thrombophilia testing in children with venous access–
associated thrombosis and no positive family history.3

Our ability to conserve our supply of blue top tubes would greatly benefit from the quality improvement objectives of the Choosing Wisely campaign!

In June 2021, the College of American Pathologists issued formal recommendations outlining practical steps to ameliorate the blue top tube shortage:

  • Evaluate the clinical necessity of coagulation testing.
  • Where possible, reduce the frequency of standing PT/INR orders, especially for stable patients on long-term warfarin.
  • Reduce routine coagulation testing where not clinically necessary, for example, routine preoperative testing for low-risk surgeries without a clinical indication.
  • Do not draw blue top tubes without a specific order. Avoid the so-called "hold" and "rainbow" draws and do not use blue tops as discard tubes.

Hopefully, prudent practices and wise choices by the medical community will alleviate demand for blue top tubes and help us avoid a disastrous interruption in our ability to evaluate and care for our patients. Just "singing the blues" won't do it! Hematologists need to lead educational efforts regarding the practical and quality-improving steps that can be taken to reduce use of blue top tubes. Systems hematologists are in an ideal position to lead these initiatives, but we can only help palliate the blue top tube supply crisis. As with all other aspects of the COVID-19 crisis, calming the storm ultimately hinges on vaccination, which would in turn result in reduced demand for coagulation testing and its downstream impacts.


  1. Choosing Wisely. American Society of Hematology. December 4, 2013. Accessed July 12, 2021.
  2. Choosing Wisely. American Society for Clinical Pathology. February 21, 2013. Accessed July 12, 2021.
  3. O'Brien SH, Badawy SM, Rotz SJ, et al. The ASH-ASPHO Choosing Wisely Campaign: 5 hematologic tests and treatments to question [published online ahead of print, 2021 May 28]. Pediatr Blood Cancer. Doi: 10.1002/pbc.28967.


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