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Hematology at a Glance

Study guide:



  • Activated protein C & S will inhibit factors 5 and 8:

    • Thus, inhibiting coagulation.

  • Factor 5 leiden mutation:

    • Resistance of factor 5 to be turned off by protein C:

      • Thus, causing thrombosis.

  • Anti-thrombin III will inhibit factor 2:

    • Potentiated by heparin.

  • Vitamin K deficiency will cause elevated PT and PTT “both”.

  • Warfarin stops the extrinsic pathway:

    • You need a “gun” for the “War”!

  • Heparin inhibits the intrinsic pathway:

    • Heparin infusion need to be continuous infusion in “long” IV “line”.

  • Factors that activate the extrinsic pathway:

    • Collagen

    • Platelets

    • Prekallikren

    • HMW-kininogen



  • Factors that activate the intrensic pathway:

    • Tissue factor (thromboplastin).

  • Factor 8 deficiency= Hemophilia A.

  • Factor 9 deficiency= Hemophilia B.

Coagulation Cascade at a glance:

  1. Use regular numbers not Latin for the factors.

  2. Count from 12 to 1 in a straight line.

  3. Factors 3, 4,6 Do NOT exist in the cascade.

  4. Factors 5 and 8 are not true factors, they are cofactors:

    1. Put them above the line.

  5. Factor 7 is lucky and should always be in your pocket:

    1. Put it below the line.

  6. Factors on the straight line = INTRESNSIC pathway = PTT.

  7. Factors on the short “Gun-like” line = EXTRENSIC pathway= PT.

  8. The green triangle signifies the vitamin K dependent factors.

Normal PTT but abnormal PT in a child with hemarthrosis: suspect factor 7 deficiency!

The patient is on heparin but no response and normal PTT: suspect antithrombin III deficiency!

Newborn presented with bleeding from the umbilical stump, hemarthrosis, and hematoma. Platelet count, PT, and PTT are all normal: suspect factor 13 deficiency!


  1. Goljan, E. (2014). Rapid review pathology. Philadelphia, PA: Saunders/Elsevier.

  2. Sattar, H. (2011). Fundamentals of pathology. Chicago:

  3. Mnemonic, P., 3, M., Calling, A., Brain, B. and Residency, P. (2016). Black Friday Anemia. [online] The Barone Zone. Available at: [Accessed 10 Nov. 2016].



Written by:           Roaa Amer


Reviewed by:       Raed Alshammari

                              Mohammed Muheib

Web Publisher:    Seba AlMutairi 

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