HEMATOLOGY
THE STUDY OF BLOOD AND ITS COMPONENTS
  • About
  • Contact
  • Collecting & Processing of Blood: Pre-Analytical
  • Blood
  • Phlebotomy and Venipuncture
  • Capillary Samples & Skin Punctures
  • The Complete Blood Count (CBC) and Differential
  • Red Blood Cells
  • White Blood Cells
  • Platelets
  • Red Blood Cell Inclusions and Abnormalities
  • Anemias
  • White Blood Cell Inclusions and Abnormalities
  • Leukemias
  • Platelet Abnormalities
  • Coagulation
  • Coagulation Disorders
    • Artifacts in Peripheral Blood Smears
  • Blood Parasites
  • References
  • Hemacytometer

THE HEMOPHILIAS:

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Queen Victoria was a famous carrier of Hemophilia A and passed it down to many of her descendants
Hemophilia A is an X-linked recessive disorder as seen in the chart above and it is a genetic disorder in which a person is missing the crucial clotting factor VIII.  Out of all the hemophilic disorders, this one represents the highest of all at 80% of all cases.

Hemophilia B is also an X-linked recessive genetic disorder and patients are missing the crucial factor IX clotting factor.  Out of all cases of hemophilia, this type represents about 20% of all cases.

Hemophilia C is an autosomal disorder versus an X-linked recessive disorder as the other 2 types.  It is not X-linked, and it involves missing the clotting factor XI.  Both homozygous and heterozygous individuals show bleeding with this disorder.

Von Willebrand Disease involves missing the important von Willebrand factor.

Vitamin K deficiency is a bleeding disorder because vitamin K is needed in order for platelets to clot normally.  Because vitamin K is produced by bacteria and the diet in the intestinal tract, intestinal disorders such as gluten intolerance, Crohn's disease, cancer, ulcerative colitis, sprue, chronic diarrhea, viruses, bacterial gastroenteritis may all either temporarily or chronically affect vitamin K production, resulting in deficiency and bleeding disorders. 

Disseminated Intravascular Coagulation

Aspirin can also cause bleeding

Thrombocytopenia can cause bleeding and lack of clotting

Early liver failure

End-stage liver failure

Uremia

Congenital afibrinogenemia

Factor V deficiency

Factor X deficiency and amyloid purpura

Glanzmann's thrombasthenia

Bernard-Soulier Syndrome

Factor XII deficiency

C1INH deficiency

Tests to Check For Bleeding Disorders:

  1. Prothrombin Time (PT)
    1. Evaluates a person's ability to form blood clots
    2. Measures the number of seconds it takes for a blood clot to form in a person's blood sample once specific reagents have been added
    3. Assesses Factors XII, XI, IX, VIII, X, V, II, and I and prekallikrein (PK) and high molecular weight kininogen (HK)
  2. INR (International Normalized Ratio)
    1. A calculation based on results of the PT test
    2. Useful for monitoring patients who are on blood-thinning anticoagulants such as warfarin (Coumadin) or Heparin
    3. Adjusts for the changes in PT reagents so different laboratories can be compared
  3. Partial Thromboplastin Time (PTT or aPTT)
    1. Often performed with the PT
    2. Assesses the blood coagulation (clotting) factors (proteins)
      1. Amount (needs to be a sufficient quantity)
      2. Function (each must function properly)
      3. Too little: excessive bleeding
      4. Too many: excessive clotting
  4. Bleeding Time (BT)
  5. Platelet Count (Estimate)

BLOOD CLOTS:

Medications to Treat Blood Clotting: Anticoagulants

Warfarin/Coumadin

Heparin
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Clotting Factors:

  • Factor I (Fibrinogen)
  • Factor II (Prothrombin)
  • Factor V
  • Factor VII
  • Factor X
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