CAP Pro Course - Hematology - Common Coagulation Tests (2025 & 2026)

Author: Margaret Reinhart, MS, MT(ASCP)
Reviewer: Laurie Bjerklie, MA, MLS(ASCP)CM

Continuing Education Credits

Objectives

  • Identify preanalytical factors that could affect coagulation testing, explain the error that would result from each factor, and recommend how to resolve the errors.
  • Identify the coagulation factors associated with the pathways in secondary hemostasis and correlate the prothrombin time (PT) and activated partial thromboplastin time (aPTT) tests with each of the pathways.
  • Predict which coagulation pathway(s) were affected by a factor deficiency or by a therapeutic treatment based on the results of the PT and aPTT test; calculate the INR based on the PT and understand its therapeutic potential.
  • Discuss the principles and procedures of PT/aPTT mixing studies, factor assays, and the thrombin time (TT) test in the diagnosis and monitoring of coagulopathies.
  • Describe the role of fibrinogen, as well as the process of fibrinolysis.
  • Correlate D-dimer test results with fibrinolysis and explain why D-dimer has a very high negative predictive value.

Course Outline

  • Identify preanalytical factors that could affect coagulation testing, explain the error that would result from each factor, and recommend how to resolve the errors.
      • Preanalytical Factors Affecting Coagulation Tests
      • Other Factors That May Affect Coagulation Tests
      • Routine PT and aPTT tests ordered on a preoperative patient with a hematocrit of 61% are both prolonged. A new sample is then requested. What should b...
      • A new member of the pediatric phlebotomy team is frequently submitting specimens for PT and aPTT testing that are slightly underfilled. She claims tha...
      • Should hemolyzed specimens be rejected for PT and aPTT testing?
      • A patient's PT test is prolonged past the instrument's reporting limits. Which of the following is the most likely cause?
  • Identify the coagulation factors associated with the pathways in secondary hemostasis and correlate the prothrombin time (PT) and activated partial thromboplastin time (aPTT) tests with each of the pathways.
      • Hemostasis
      • Secondary Hemostasis
      • Prothrombin Time (PT) Testing
      • PT Testing and International Normalized Ratio (INR) Reporting
      • Activated Partial Thromboplastin Time (aPTT) Testing
      • Basics on Coagulation Testing Instrumentation
      • A patient on warfarin therapy has an INR result of 1.4.Given the fact that this patient is on anticoagulant therapy, what is the significance of this ...
      • A blood sample from a patient known to have factor VIII deficiency has been received in the laboratory for therapeutic testing. Which of the following...
      • Which one of the following factors is impacted by warfarin therapy?
      • A patient is being treated with intravenous heparin therapy following an acute myocardial infarction. Which coagulation screening test most appropriat...
  • Predict which coagulation pathway(s) were affected by a factor deficiency or by a therapeutic treatment, based on the results of the PT and aPTT test; calculate the INR based on the PT and understand its therapeutic potential.
      • Coagulation Testing and Patient Treatment
      • Mechanism of Action of Common Anticoagulant Drugs
      • The following laboratory results have been obtained for a 40-year-old patient:TestPatient ResultNormal RangeProthrombin time (PT)20 seconds11 – ...
      • A patient on anticoagulation therapy presents with a prolonged PT and an INR of 4.2. What anticoagulant drug is this patient taking and do you think t...
      • A patient is being treated with dabigatran, an anticoagulant drug. Which test would you use to monitor their therapy?
      • Which test can detect defects or deficiencies of coagulation factors in the common pathway?
  • Discuss the principles and procedures of PT/aPTT mixing studies, factor assays, and the thrombin time (TT) test in the diagnosis and monitoring of coagulopathies.
      • Mixing Studies
      • Thrombin Time Assay
      • Factor Assays
      • A 4-year-old patient presents to the emergency department (ED) with hematuria and a family history of bleeding disorders. The patient's coagulation te...
      • Mixing studies are performed on a patient who has a prolonged aPTT but a normal PT. The aPTT remained prolonged after the addition of normal pooled pl...
      • A patient is being evaluated for a possible bleeding disorder. The thrombin time (TT) was prolonged at 42 seconds (reference range <20 seconds). Wh...
      • Which one of the following tests is used to determine if heparin contamination is present in a patient sample?
  • Describe the role of fibrinogen, as well as the process of fibrinolysis. Correlate D-dimer test results with this process, and explain why D-dimer has a very high negative predictive value.
      • Fibrinogen
      • Fibrinolytic System
      • D-dimer
      • A patient presents to the Emergency Department with complaints of fatigue, abdominal pain, nausea, and swelling in the legs. It is also noted that the...
      • Coagulation screening tests, including PT, aPTT, and fibrinogen levels, are run on a 38-year-old pregnant patient. All three test results fell within ...
      • What is the end product of the coagulation cascade?
      • Which of the following fibrinogen test results is expected if a patient is experiencing a normal, uncomplicated pregnancy?
  • References
      • References

Additional Information

Level of Instruction: Intermediate
Intended Audience: This program is designed as an educational and training tool for MLS, MT, and MLT personnel, medical laboratory science students, pathology residents, and practicing pathologists.
Author Information: Margaret Reinhart MS, MT(ASCP) is the MLS Program Director and Senior lecturer in Biological Sciences at the University of the Sciences in Philadelphia PA where she teaches hematology, clinical immunology, parasitology, and other related courses. She is also an adjunct instructor in Hematology at Pennsylvania Hospital, Philadelphia PA. She holds a Masters Degree in Biology and in Health Care Administration.
Reviewer Information: Laurie Bjerklie, M.A., MLS(ASCP)CM, is currently an Educational Developer. She earned a B.S. in Medical Laboratory Science from the University of North Dakota and an M.A. in Curriculum and Instruction from Saint Xavier University. She has over 15 years of experience in higher education and has held faculty positions in both MLT and MLS programs. 

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