Diagnostic Blood Tests

Diagnostic Blood Tests

Fresh whole blood for laboratory testing is usually collected from a superficial vein, to check the efficiency of gas exchange. It may be necessary to collect a blood sample from an artery. Various changes in the blood can reveal many different health conditions. The presence of leukocytosis signifies infections. When infections are severe, the hematocrit will have a buffy coat that is larger than normal. Diabetics regularly test their own blood to control their blood sugar levels and make smart dietary choices. Lipidemia causes the blood to have a yellowish tint, whereas anemia causes the blood to appear pale, with a low hematocrit. The size and shape of erythrocytes under the microscope may indicate pernicious or iron-deficiency anemias.

An effective diagnostic testing method is the differential WBC count. This test determines rela-tive proportions of various types of leukocytes. For example, if eosinophils are high, the patient may have significant allergies or even a parasitic infection. The state of a person’s hemostasis can be gauged via the prothrombin time test, which determines the abil-ity of normal clotting to occur. If thrombocytopenia is suspected, the platelet count is taken. If platelet counts exceed 1 million per microliter, thrombocyto-sis is present. For routine physical examinations andbefore hospitalization, a complete blood count (CBC) and a ­computerized sequential multiple analysis test (SMAC) are performed. The CBC includes counts of the formed elements, hematocrit, hemoglobin con-tent, and RBC size. The second test, also known as the SMAC, chemistry­panel, and comprehensive met-abolic panel, measures electrolytes, glucose, and var-ious markers that signify kidney and liver conditions. Together, the CBC and SMAC give an accurate and comprehensive view of a person’s overall health.