Tumor Necrosis Factor Build info

Synonyms

• TUMOR NECROSIS FACTOR
• TNF
• LAB11087

Procedure Name

TUMOR NECROSIS FACTOR

Procedure Master Number

LAB11087

Procedure ID

114570

Clinical Info

This test is used for measurement of Tumor Necrosis Factor-α levels in serum.

Specimen Sources

Specimen Types

Container

Gold Top Tube

Collection Instructions

Container/Tube: Gold top
Specimen: 1 mL (minimum volume: 0.4 mL) of serum
Transport Temperature: Frozen
Collection:
Allow blood sample collected in serum
separator tube to clot at room temperature for
30 minutes prior to centrifugation. Allowing
samples to sit on the clot for more than 30
minutes may result in higher TNF-alpha levels

Specimen Volume

1 mL (minimum volume: 0.4 mL) of serum

Transport Instructions

Frozen

Specimen Stability

Methodology

Enzyme-Linked Immunosorbent Assay (ELISA)

Days Performed

Tuesday a.m.

Performing Laboratory

LabCorp of America

CPT

83520

PDM

Only Orderable at Locations:

Results

Result Interpretation

0.0- 2.2  pg/mL
 
Tumor necrosis factor-α (cachectin) and tumor necrosis factor-β (lymphotoxin) are two closely related proteins that share sequence homology of 34% in their amino acid sequence. Both mediators act on their target cells via the same receptors and, therefore, show similar, but not identical, biological effects. Under denaturing conditions TNF-α is a 17-kilodalton, nonglycosylated protein. The biologically active form of TNF-α is a trimer. Besides this soluble form of TNF-α, a 28-kilodalton membrane-bound form occurs on cell surfaces of TNF-producing cells, which may serve as a pool for soluble TNF-α and can be proteolytically cleaved from the cell surface.
Different cells are shown to produce TNF-α: For example, macrophages, CD4⁺ T cells and NK cells after stimulation with lipopolysaccharides. Additionally, smooth muscle cells, polymorphonuclear neutrophils, astrocytes and a variety of tumor cell lines can produce TNF-α. TNF-α acts via two distinct cell surface receptors, which are called TNF receptor I, and TNF receptor II. These receptors can be identified on virtually all cell types except erythrocytes. Besides the cell-bound forms of TNF receptors, soluble forms are known to be capable of TNF-α binding. They compete, therefore, with the cell-bound forms and can inhibit the effects of TNF-α.
Due to the occurrence of TNF-α receptors on nearly all cells, TNF-α demonstrates a wide variety of biological action. It has cytolytic and cytostatic effects on tumor cells and shows chemotactic activity on neutrophils. TNF-α is a growth factor for fibroblasts and stimulates the synthesis of collagenase and prostaglandin E₂ bone resorption can be induced by TNF-α because it activates osteoclasts. TNF-α enhances the proliferation of T cells after stimulation with IL-2. In the absence of IL-2, TNF-α induces the proliferation and differentiation of β cells.
TNF-α serum or plasma levels may be elevated in sepsis, autoimmune diseases, various infectious diseases, and transplant rejection.

Forms