serum

(sîr'əm)
n., pl., se·rums, or se·ra (sîr'ə).

1. The clear yellowish fluid obtained upon separating whole blood into its solid and liquid components after it has been allowed to clot. Also called blood serum.
2. Blood serum from the tissues of immunized animals, containing antibodies and used to transfer immunity to another individual.
3. Watery fluid from animal tissue, such as that found in edema.
4. Whey.

[Latin, whey, serum.]

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The liquid portion that remains when blood is allowed to clot spontaneously and is then centrifuged to remove the blood cells and clotting elements. It has approximately the same volume (55%) as plasma and differs from it only by the absence of fibrinogen. See also Fibrinogen.

Blood serum contains 6–8% solids, including macromolecules such as albumin, antibodies and other globulins, and enzymes; peptide and lipid-based hormones; and cytokines; as well as certain nutritive organic materials in small amounts, such as amino acids, glucose, and fats. Somewhat less than 1% of the serum consists of inorganic substances. Small amounts of respiratory gases are dissolved in the serum, as is the gas nitric oxide, which serves as a chemical messenger and vasodilator. Small amounts of waste material are also present. These substances, along with other small molecules which are not bound to blood proteins, are filtered out as blood flows through the kidney. See also Blood; Clinical pathology; Kidney.

Certain types of sera, both human and animals, are used in clinical medicine. Immune serum and hyperimmune serum either are developed by naturally occurring disease or are deliberately prepared by repeated injection of antigens to increase antibody titer for either diagnostic tests or the treatment of active disease. These sera are referred to as antisera, since they have a specific antagonistic action against specific antigens. See also Antibody; Antigen; Biologicals; Immunity.

By custom, the clear portion of any liquid material of animal origin separated from its solid or cellular elements is also referred to as sera. These fluids are more properly referred to as effusions. See also Serology.

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Clear liquid left after the protein has been clotted; the serum from milk, occasionally referred to as lacto-serum, is whey.

Blood serum is blood plasma without the fibrinogen. When blood clots, the fibrinogen is converted to fibrin, which is deposited in strands that trap the red cells and form the clot. The clear liquid that is exuded is the serum. See also blood clotting.

The clear watery body fluid exuded by a serous membrane. Blood serum is the amber-coloured, non-cellular, fluid part of blood, excluding fibrinogen and platelets.

IN BRIEF: The yellow liquid in blood that comes from separating whole blood into its liquid and solid forms when a clot forms; a cure, antitoxin.

Loving is the only sure road out of darkness, the only serum known that cures self-centeredness. — Roger M'Ckuen.

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a plural of serum.

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Pl. sera, serums [L.] the clear portion of any animal or plant fluid that remains after the solid elements have been separated out. The term usually refers to blood serum, the clear, straw-colored, liquid portion of the plasma that does not contain fibrinogen or blood cells, and remains fluid after clotting of blood.
Blood serum from animals whose bodies have built up antibodies is called antiserum or immune serum. Inoculation with such an antiserum provides temporary, or passive, immunity against the disease.

• s. albumin mastitis test — a high concentration of serum albumin in milk indicates the presence of mastitis in the quarter.
• antilymphocyte s. — see antilymphocyte serum.
• s. breaks — in classical swine fever (hog cholera) vaccination when a serum-simultaneous vaccination program is not effective and it is assumed that the hyperimmune serum was ineffective.
• s. clot time — see prothrombin consumption test.
• s. enzymes — enzymes of individual tissues are released into the blood when the tissue is damaged or when there is much activity in it. The levels are used as a measure of activity or injury.
• s.-fast — resistant to the effects of serum.
• s. glutamic–oxaloacetic transaminase (SGOT) — see aspartate aminotransferase.
• s. glutamic–pyruvic transaminase (SGPT) — see alanine aminotransferase.
• immune s. — serum from an immunized animal, containing specific antibody or antibodies.
• s. osmolality — a measure of the number of dissolved particles per unit of water in serum. See also serum osmolality.
• pooled s. — the mixed serum from a number of animals.
• s. protein — see serum protein.
• s. sickness — a group of immediate or antibody-mediated hypersensitivity reactions (also referred to as type III hypersensitivities) that includes Arthus reaction, serum sickness and immune complex diseases. The pathogenesis involves formation of bulky antibody–antigen complexes in the walls of small blood vessels; the complexes fix complement and cause necrosis and thrombus formation. There is infiltration of polymorphonuclear cells from which lysosomal enzymes are released.
• s.-simultaneous immunization — an outdated method of vaccination, most popular at one time in the vaccination of pigs against classical swine fever (hog cholera). Live virus and antiserum to the virus were injected into the patient simultaneously; breakdowns in the system were frequent, leading to severe outbreaks of the target disease.
• s. thymic factor — a humoral factor enhancing T lymphocyte responsiveness.

(sir′um)
n

The fluid component of the blood containing all stable constituents except fibrinogen. When blood is allowed to clot and stand, a clear yellowish fluid, the serum, separates.

For a list of words related to serum, see:

• Heart and Circulatory and Lymphatic Systems - serum: liquid obtained from clotted blood; form of plasma
• Diagnostic Terminology - serum: fluid that separates from clotted blood or standing blood plasma
• Physiology - serum: liquid portion of coagulated blood
• PHARMACOLOGY - serum: blood serum that contains agents of immunity used as antitoxin

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See words rhyming with "sera."

  See crossword solutions for the clue Serum.

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Dansk (Danish)
n. - serum

Nederlands (Dutch)
serum

Français (French)
n. - sérum

Deutsch (German)
n. - Serum

Ελληνική (Greek)
n. - τυρόγαλο, (ιατρ.) ορός

Italiano (Italian)
siero

Português (Portuguese)
n. - soro (m), sero (m)

Русский (Russian)
сыворотка (крови)

Español (Spanish)
n. - suero

Svenska (Swedish)
n. - serum

中文（简体）(Chinese (Simplified))
浆液, 免疫血清, 血清

中文（繁體）(Chinese (Traditional))
n. - 漿液, 免疫血清, 血清

한국어 (Korean)
n. - 장액, 혈청 , (우유의) 유장

日本語 (Japanese)
n. - 漿液, 血清

العربيه (Arabic)
‏(الاسم) ألمصل " مصل ألدم أو ألنبات "‏

עברית (Hebrew)
n. - ‮נוזל הדם, נוזל-חיסון, נוזל לאבחון מחלה‬

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