Synonym/Acronym
IgA, IgD, IgG, IgM.
Rationale
To quantitate immunoglobulins A, D, G, and M as indicators of immune system function, to assist in the diagnosis of conditions that result in deficient or excessive production of immunoglobulins; to investigate immune system disorders such as multiple myeloma. To assess IgE levels in order to identify the presence of an allergic or inflammatory immune response.
Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction.
Normal Findings
Method: Nephelometry for IgA, IgD, IgG, IgM; Fluorescent enzyme immunoassay for IgE.
| Age | Conventional Units | ||
|---|---|---|---|
| IgA (SI = CU × 0.01) | IgG (SI = CU × 0.01) | IgM (SI = CU × 0.01) | |
| Newborn–2 yr | 2–126 mg/dL | 242–1,108 mg/dL | 21–215 mg/dL |
| 3–4 yr | 14–212 mg/dL | 485–1,160 mg/dL | 26–155 mg/dL |
| 5–9 yr | 52–226 mg/dL | 514–1,672 mg/dL | 26–188 mg/dL |
| 10–14 yr | 42–345 mg/dL | 581–1,652 mg/dL | 47–252 mg/dL |
| 15–18 yr | 60–349 mg/dL | 479–1,433 mg/dL | 26–232 mg/dL |
| 18 yr–adult | 68–408 mg/dL | 768–1,632 mg/dL | 35–263 mg/dL |
| IgD (SI = CU × 10) | |||
| Less than 15 mg/dL | |||
| IgE Conventional and SI Units | |||
| Less than 1 yr | Less than 35 kU/L | ||
| 1–2 yr | Less than 98 kU/L | ||
| 3 yr | Less than 200 kU/L | ||
| 4–6 yr | Less than 308 kU/L | ||
| 7–8 yr | Less than 404 kU/L | ||
| 9–12 yr | Less than 697 kU/L | ||
| 13–15 yr | Less than 630 kU/L | ||
| 16–17 yr | Less than 538 kU/L | ||
| 18 yr and older | Less than 215 kU/L |
(Study type: Blood collected in a gold-, red-, or red/gray-top tube; related body system: .)
Immunoglobulins A, D, E, G, and M are made by plasma cells in response to foreign substances. Immunoglobulins neutralize toxic substances, support phagocytosis, and destroy invading microorganisms. They are made up of heavy and light chains. Immunoglobulins produced by the abnormal proliferation of a single plasma cell (clone) are called monoclonal. Polyclonal increases result when multiple cell lines produce excessive amounts of antibody.
IgA is found mainly in secretions such as tears, saliva, and breast milk. It is believed to protect mucous membranes from viruses and bacteria.
The function of IgD is not well understood, but it is believed to interact directly with microorganisms and participate in the activation of B lymphocytes, mast cells, and monocytes.
IgG is the predominant serum immunoglobulin and is important in long-term defense against disease. It is the only antibody that significantly crosses the placenta.
IgM is the largest immunoglobulin, and it is the first antibody to react to an antigenic stimulus. IgM also forms natural antibodies, such as ABO blood group antibodies. The presence of IgM in cord blood is an indication of congenital infection.
IgE is an antibody whose primary response is to allergic reactions and parasitic infections. Most of the body’s IgE is bound to specialized tissue cells; little is available in the circulating blood. IgE binds to the membrane of special granulocytes called basophils in the circulating blood and mast cells in the tissues. Basophil and mast cell membranes have receptors for IgE. Mast cells are abundant in the skin and the tissues lining the respiratory and alimentary tracts. When IgE antibody becomes cross-linked with antigen/allergen, the release of histamine, heparin, and other chemicals from the granules in the cells is triggered. A sequence of events follows activation of IgE that affects smooth muscle contraction, vascular permeability, and inflammatory reactions. The inflammatory response allows proteins from the bloodstream to enter the tissues. Helminths (worm parasites) are especially susceptible to immunoglobulin-mediated cytotoxic chemicals. The inflammatory reaction proteins attract macrophages from the circulatory system and granulocytes, such as eosinophils, from circulation and bone marrow. Eosinophils also contain enzymes effective against the parasitic invaders. A nasal smear can be examined for the presence of eosinophils to screen for allergic conditions. Either a single smear or smears of nasal secretions from each side of the nose should be submitted, at room temperature, for Hansel staining and evaluation. Normal findings vary by laboratory, but generally, greater than 10% to 15% is considered eosinophilia or increased presence of eosinophils. Results may be invalid for patients already taking local or systemic corticosteroids.
IgA, IgD, IgG, and IgM
IgE
IgA, IgD, IgG, and IgM
IgE
Other Considerations
Increased In
IgA
Polyclonal
Monoclonal
IgD
Polyclonal (pathophysiology is unclear, but increases are associated with increases in IgM)
Monoclonal
IgE
Conditions involving allergic reactions or infections that stimulate production of IgE
IgG
Conditions that involve inflammation and/or development of an infection stimulate production of IgG
Polyclonal
Monoclonal
IgM
Polyclonal (humoral response to infections and inflammation; both acute and chronic)
Monoclonal
Decreased In
IgA
IgD
IgE
IgG
IgM
Before the Study: Planning and Implementation
Teaching the Patient What to Expect
After the Study: Implementation & Evaluation Potential Nursing Actions
Treatment Considerations
Nutritional Considerations
Clinical Judgement
Follow-Up Evaluation and Desired Outcomes