Detecting and Evaluating Coagulation Inhibitors and Factor Deficiencies (Online CE Course)

(based on 318 customer ratings)

Author: Leah Coppolino, MPH, CLS(NCA), MT(ASCP)
Reviewer: Donna D. Castellone, MS, MT(ASCP)SH

What causes a patient's prothrombin time and/or activated partial thromboplastin time to be prolonged when the patient is not on anticoagulant therapy? Is it something that happened as a result of the collection process, is it related to an illness, or is it perhaps related to a factor deficiency or a circulating coagulation inhibitor? This course will acquaint you with several conditions associated with prolonged PT and aPTT test results. You will learn when it is appropriate to perform a mixing study, whether the results suggest a factor deficiency or a coagulation inhibitor, and further testing that can be done to confirm your results.

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Continuing Education Credits

P.A.C.E.® Contact Hours (acceptable for AMT, ASCP, and state recertification): 1 hour(s)
Course number 578-068-16, approved through 7/31/2018
Course number 20-547657, approved through 9/1/2018


  • Determine various causes of an elevated prothrombin time or activated partial thromboplastin time result.
  • Evaluate situations in which performing a mixing study would be appropriate.
  • List the steps involved in a prothrombin time or activated partial thromboplastin time mixing study procedure.
  • Correctly analyze and interpret mixing study results to distinguish a factor deficiency from a circulating inhibitor(s).
  • Determine which, if any, further coagulation studies would prove helpful after obtaining mixing study results.

Customer Ratings

(based on 318 customer ratings)

Course Outline

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Additional Information

Level of instruction: Intermediate

Intended Audience: Medical laboratory scientists, medical technologists, and technicians, This course is also appropriate for medical laboratory science students and pathology residents.
Author information: Leah Coppolino, MPH, CLS(NCA), MT(ASCP) is the Director of the Clinical Laboratory Science Program at St. Christopher’s Hospital for Children in Philadelphia, Pennsylvania. She holds a Masters in Public Health from Thomas Jefferson University.
Reviewer information: Donna D. Castellone, MS, MT(ASCP)SH has worked as a coagulation specialist in both clinical and commercial settings. Ms. Castellone holds a Masters Degree in Health Science and Administration from State University at Stony Brook, Stony Brook, New York. She has written over 70 articles, was a contributing author for 3 textbooks, and is a frequent lecturer at laboratory workshops.
Course description: Prolonged PT and aPTT results are caused by many different conditions. It is important for medical technologists to be able to distinguish between preanalytic causes, secondary clinical causes, and important and potentially dangerous causes such as coagulation factor deficiencies and circulating coagulation factor inhibitors. Upon completion of this course, you will be able to identify: the common causes associated with prolonged PT and/or aPTT results, when it is appropriate to perform a mixing study, how to perform and interpret mixing studies, how to differentiate between factor deficiencies and factor inhibitors, and further testing that can be done to confirm mixing study results.

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1 to 1 mix for incubation step

all 3 tubes incubating at 37 degrees for 90 minutes (or 1 hour, 30 minutes)

blue top not filled

Properly Filled Sodium Citrate Tube

updated coag cascade 4-2014 LC