Understanding Clinical Pathology Services
The purpose of hematology testing is to determine the amount of different blood cells (including, but not limited to white blood cells, red blood cells, and platelets), and from these values, determine the effect of the test article being evaluated.
Clinical chemistry testing accurately measures concentrations of chemical compounds (analytes) in serum, plasma, and other bodily fluids. The results of these measurements may then be used to evaluate physiological processes underway in the organism at the time of specimen collection. Clinical chemistry data may be used to evaluate the safety of medical implants, pharmaceuticals, and to assist in the diagnosis of diseases. Concentrations of specific biochemicals in test samples may be influenced by a number of pre-analytical, analytical, and post-analytical variables as well as pathologic processes. To properly interpret clinical data, one must take into account all possible sources of variation, method limitations, and measurement uncertainty.
Urinalysis is a test of the microscopic and chemical constituents of urine. It can be used to assess the effect of a treatment on kidney and urinary tract function and basic health. In the microscopic segment of the analysis, bacteria, crystals and other elements are assessed and in the visual and chemistry portions, pH, blood, color, clarity and other analytes are evaluated.
Coagulation tests are employed to diagnose various bleeding disorders.
The Prothrombin Time (PT)
The PT assay measures the effect of a test article on the clotting time for blood activated via the extrinsic pathway. The PT time is obtained when an excess of thromboplastin and optimum calcium chloride are added to citrated plasma under standardized conditions.
The Activated Partial Thromboplastin Time (APTT)
The APTT assay measures the clotting time of blood with one less variable than the Prothrombin Time (PT) assay. In the APTT, the calcium ions and phospholipids that substitute for platelet phospholipids are added to blood plasma. The generation of fibrin is the endpoint. Clinically, the APTT is used to identify and quantitate deficiencies in the intrinsic clotting pathway after the addition of the activator and to control anticoagulant therapy.
Bone Marrow Evaluation
Bone marrow is evaluated as a part of pathological analysis in order to evaluated the blood cells within the bone marrow as well as its organization and structure. The pathologist compares the results of the bone marrow evaluation to those of the hematology analysis (Complete Blood Count – CBC) in order to assess if the marrow is healthy and producing blood cells as intended.