Serum specimens can be centrifuged only after clotting is completed. All specimens for tests carried out on serum or plasma must be centrifuged to separate the liquid from the cellular portions of the blood. However, plasma specimens that are collected in tubes with anticoagulant can be centrifuged immediately. It is important to avoid recentrifugation because this may result in hemolysis and can alter the testing results.

If a patient is undergoing analysis of gastric fluids before and after a gastric stimulant, the blood test that the phlebotomist is likely to need to collect a specimen for is serum gastrin, which evaluates gastric production. The serum is collected in a red- or gray-topped tube. Gastric fluid analysis and serum gastrin are tested to help diagnose chronic gastritis, chronic renal failure, gastric and duodenal ulcers, gastric carcinoma, G-cell hyperplasia. pernicious anemia, pyloric obstruction, and hyperparathyroidism.

If the phlebotomist is asked to transport a nonblood specimen, such as a urine sample, to the laboratory for testing, the phlebotomist should verify that the specimen is labeled correctly. The label should be on the container and not the lid (which must be removed for testing) and should contain the same type of identifying information as on the blood sample containers. Additionally, the type and source of the sample should be identified on the label because different types of samples may have similar appearances.

The main component of erythrocytes (RBCs) is hemoglobin. Hemoglobin is a complex protein that contains iron; it carries oxygen throughout the body and carries C02 back to the lungs. Erythrocytes are the most plentiful blood cells; there are 4.5-5 million per cubic milliliter of blood. They are concave discs that lack nuclei and have a life expectancy of approximately 120 days. Erythrocytes are produced in the bone marrow in a process called erythropoiesis.