A specimen collected for chemistry is usually what type of sample?

In the context of specimens collected for chemistry testing in a medical laboratory, plasma and serum are the primary types of samples used. Plasma is the liquid component of blood that contains water, electrolytes, proteins, and other substances, and it is obtained when blood is collected in a tube containing anticoagulants that prevent clotting. Serum, on the other hand, is derived from clotted blood after the clot has been removed and consists of the liquid left after blood coagulation.

Chemistry tests are often performed on these components because they provide essential information about various biochemical substances in the body, including enzymes, electrolytes, and hormones. The composition of plasma and serum reflects the metabolic state of the individual, making them highly relevant for analysis in routine laboratory tests.

While whole blood can also be analyzed for some chemistry tests, plasma and serum are preferred due to their stability and the clarity of the sample, which can reduce interference from cellular components. Other types of specimens, such as urine and cerebrospinal fluid, are used for specific tests but do not represent the primary type of sample for general chemistry testing.