Hematology is the branch of medicine concerned with the study, diagnosis, treatment, and prevention of diseases related to the blood. It involves treating diseases that affect the production of blood and its components, such as blood cells, hemoglobin, blood proteins and the mechanism of coagulation.
Some examples of tests performed in the hematology department at the OSF HealthCare Saint Francis Medical Center Laboratory include:
- Complete Blood Count: A count of the total number of red blood cells, white blood cells and platelets present in blood, as well as calculations of parameters associated with them.
- Erythrocyte sedimentation rate (ESR): Measurement of the rate at which red blood cells sediment in a period of one hour.
- Reticulocyte count: Percentage of immature red blood cells which can help diagnose anemias, and determine the effectiveness of treatments.
- Cerebrospinal fluid cell count and differential: Detection of Meningitis, Encephalitis, Multiple Sclerosis, hemorrhage, abscess, tumor, and other infections.
- Screening for sickle-cell disease: Inherited trait that affects 8% of African-Americans, where red blood cells are “C” shaped and rigid, vs circular and flexible.
- Flow Cytometry: A specialized department that uses a laser based, biophysical technology to diagnose blood, tissue and bone marrow disorders.
Coagulation tests measure the ability of blood to clot, as well as how long it takes. They are usually ordered when someone is experiencing abnormal bleeding or bruising. Testing can assess the risk of excessive bleeding or the formation of clots (thrombosis) somewhere in the blood vessels.
Prothrombin time (PT), International Normalized Ratio (INR), Activated Partial Thromboplastin Time (aPTT), and Thrombin Time (TT) tests are sometimes ordered before a patient undergoes surgery or to check medication levels, such as in patients who are on anticoagulant drugs. D-dimers are ordered to check for thrombotic activity and disorders by measuring a small protein fragment of a degraded blood clot.
Routine Coag Tests Performed
|Test Name||Frequency performed||OSF TAT|
|Prothrombin Time w/ INR||Daily||< 1 day*|
|Prothrombin Time Mixing Studies||M-F AM shift||1-2 days|
|Activated Partial Thromboplastin Time||Daily||< 1 day*|
|Activated Partial Thromboplastin Time Mixing Studies||M-F AM shift||1-2 days|
|Circulating PTT Inhibitor||M-F AM shift||1-2 days|
|Fibrinogen||Daily||< 1 day*|
|Thrombin Time||M-F AM shift||1-2 days|
|Platelet Function Assay||Daily||< 1 day*|
|Coagulation Profile (PT, PTT, Fibrinogen)||Daily||< 1 day*|
|D-Dimer (Quantitative)||Daily||< 1 day*|
|Coagulation Profile w/ D-Dimer||Daily||< 1 day*|
|Protein C Activity||M-F AM shift||1-2 days|
|Protein S Activity||M-F AM shift||1-2 days|
|Antithrombin 3, Functional||Daily||1 day|
|Lupus Anticoagulant Screen (Dilute Russell Viper Venom Test)||M-F AM shift||2 days|
|Heparin Dependent Antibody Screen (PF4IgG)||M-F AM shift||1 day|
|Low Molecular Weight Heparin Assay (Anti XA)||Daily||1 day|
*< 1 day TAT for a local client means tests are generally resulted in a matter of hours, including transport time.
Factor activity may be measured when someone is suspected of having an acquired condition that is causing bleeding, such as vitamin K deficiency or liver disease. Sometimes factor testing may be done on a person with a known deficiency to monitor the factor deficiency and to evaluate the effectiveness of treatment. A few of the Factor assays performed routinely are:
Routine Factor Assays Performed
|Test Name||Frequency performed||OSF TAT|
|Factor II Activity||M-F AM shift||1 day|
|Factor IX Activity||M-F AM shift||1 day|
|Factor IX Inhibitor||M-F AM shift||1-2 days|
|Factor V Activity||M-F AM shift||1 day|
|Factor V Leiden Screen Activated Protein C Resistance||M-F AM shift||2-3 days|
|Factor VII Activity||M-F AM shift||1 day|
|Factor VIII Activity||M-F AM shift||1 day|
|Factor VIII Inhibitor||M-F AM shift||1-2 days|
|Factor X Activity (not anti-XA)||M-F AM shift||1 day|
|Factor XI Activity||M-F AM shift||1 day|
|Factor XII Activity||M-F AM shift||1 day|
|Von Willebrand Factor Antigen||M-F AM shift||1 day|
Many clinical conditions can lead to unexplained bleeding and can be tested for as well. Some examples are:
- Congenital hemophilia - This classic bleeding disorder is an X-linked, recessive genetic abnormality. Males with one copy of the defect are affected; however, females are asymptomatic carriers. The disease originates from one of two altered proteins in the coagulation cascade, Factor VIII (hemophilia A) or Factor IX (hemophilia B), which are indistinguishable clinically.
- Von Willebrand Disease - Defective synthesis or release of functional Von Willebrand Factor (VWF) causes defective platelet adhesion and leads to a spectrum of conditions, such as epistaxis, heavy menstrual bleeding, and easy bruising.
- Antiphospholipid syndrome - An autoimmune prothrombotic acquired condition, Antiphospholipid Syndrome (APLS) is frequently associated with a markedly prolonged aPTT, leading to a concern that the affected individual might be at risk for a major hemorrhage. Not only is this highly unlikely, but as a prothrombotic state, APLS is typically associated with venous thromboembolism and/or arterial thrombosis.
- Acquired hemophilia - Although rare, acquired hemophilia results from spontaneous formation of autoantibodies to Factor VIII in a previously healthy individual, either male or female. As the name suggests, there is no overt genetic component. Factor VIII activity is significantly decreased as a result of the autoantibodies, and severe and uncontrolled bleeding results.