American Society for Clinical Laboratory Science

View all recommendations from this society

September 13, 2021

Do not order a homocysteine assay as part of the thrombophilia work up.

For long it was thought that elevated homocysteine was associated with cardiovascular diseases. That in turn could lead to coronary artery disease, heart attacks, strokes, clots in veins causing deep vein thrombosis (DVT) and pulmonary embolism (PE), and pregnancy complications among others. But in 2010 the American Heart Association declared that elevated homocysteine levels were not considered to be a major risk factor for cardiovascular disease. Subsequently, in 2013, the American College of Obstetricians and Gynecologists recommended that fasting homocysteine levels should not be ordered as part of work up for venous thromboembolism. Homocysteine is a breakdown product of methionine that can be recycled by the human body with the help of the enzyme methylene tetrahydrofolate reductase (MTHFR) to reuse in building proteins. A mutation of the MTHFR gene (C677T) impairs its ability to process folate that may lead to elevated homocysteine levels. An elevated homocysteine level is not a clotting disorder and should not be included in thrombophilia testing panels.

These items are provided solely for informational purposes and are not intended as a substitute for consultation with a medical professional. Patients with any specific questions about the items on this list or their individual situation should consult their physician.

How The List Was Created

George Fritsma, MS, MLS (ASCP), and the late Cindy Johns, MS, MLS (ASCP) hosted a plenary presentation “Enhancing Laboratory Communication to Reduce Extra-analytical Errors” at the ASCLS Clinical Laboratory Educators’ Conference in Boston in February 2017. Their talk referenced the ABIMF Choosing Wisely initiative. Subsequent discussions resulted in the ASCLS Board of Directors appointing a Choosing Wisely task force that evolved to a standing committee. The committee is composed of ASCLS members representing all medical laboratory science disciplines.

The committee collaborated with respective ASCLS Scientific Assemblies in developing and reviewing recommendations, which the Board of Directors reviewed and accepted for publication. The recommendations were subsequently reviewed in collaboration with the ASCP Test Utilization Steering Committee prior to submission.



American Society for Clinical Laboratory Science (ASCLS) recommendations were developed under the leadership of ASCLS’s Choosing Wisely Committee and the ASCLS president and executive vice president. The Committee examined numerous options based on evidence available through an extensive review of  the literature and member proposals. Subject matter experts from the ASCLS Scientific Assemblies reviewed and recommended approval of their respective recommendations, which are subsequently approved by the ASCLS Board of Directors. The recommendations were subsequently reviewed in collaboration with the ASCP Test Utilization Steering Committee prior to submission.