What is the fluid portion of a blood sample known as when anticoagulant is added?

The fluid portion of a blood sample that remains after the addition of an anticoagulant is referred to as plasma. When anticoagulants are used, they prevent the blood from clotting, thus allowing the components of blood to remain suspended in liquid form. Plasma comprises not only water but also various proteins, electrolytes, nutrients, hormones, and waste products, which are essential for many physiological functions and are critical for diagnostic purposes in laboratory analysis.

In contrast, serum is the fluid that separates from the blood after it has clotted and does not contain clotting factors like fibrinogen. Antiserum is a type of serum that contains specific antibodies against a particular antigen, and blood complement refers to a group of proteins in the blood serum that work with antibodies to help destroy pathogens. Understanding these distinctions is crucial, especially in medical diagnostics and treatment, as the choice between using plasma or serum can affect the results of various laboratory tests.