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Interpretive Handbook

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Test 62046 :
Respiratory Profile, Region 1, North Atlantic (CT, MA, ME, NJ, NH, NY, PA, RI, VT)

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Specific IgE:

Clinical manifestations of immediate hypersensitivity (allergic) diseases are caused by the release of proinflammatory mediators (histamine, leukotrienes, and prostaglandins) from immunoglobulin E (IgE)-sensitized effector cells (mast cells and basophils) when cell-bound IgE antibodies interact with allergen.

 

In vitro serum testing for IgE antibodies provides an indication of the immune response to allergen that may be associated with allergic disease.

 

The allergens chosen for testing often depend upon the age of the patient, history of allergen exposure, season of the year, and clinical manifestations. In individuals predisposed to develop allergic disease, the sequence of sensitization and clinical manifestations proceed as follows: eczema and respiratory disease (rhinitis and bronchospasm) in infants and children <5 years due to food sensitivity (milk, egg, soy, and wheat proteins) followed by respiratory disease (rhinitis and asthma) in older children and adults due to sensitivity to inhalant allergens (dust mite, mold, and pollen inhalants).

 

Total IgE:

IgE antibodies mediate allergic diseases by sensitizing mast cells and basophils to release histamine and other inflammatory mediators on exposure to allergens.

 

Serum levels of IgE are increased in many patients with allergic diseases, parasitic diseases, allergic bronchopulmonary aspergillosis, and the rare hyper IgE syndrome

Useful For Suggests clinical disorders or settings where the test may be helpful

Specific IgE:

Establishing the diagnosis of an allergic disease and defining the allergens responsible for eliciting signs and symptoms

 

Assessing sensitization to respiratory allergens commonly found in the North Atlantic region including Connecticut, Maryland, Maine, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, and Vermont

 

Total IgE:

An initial (screening) test for allergic disease

Interpretation Provides information to assist in interpretation of the test results

Specific IgE:

Detection of IgE antibodies in serum (Class 1 or greater) indicates an increased likelihood of allergic disease as opposed to other etiologies and defines the allergens that may be responsible for eliciting signs and symptoms.

 

The level of IgE antibodies in serum varies directly with the concentration of IgE antibodies expressed as a class score or kU/L.

 

Total IgE:

Serum levels of IgE greater than the mean +1 standard deviation (SD) for age suggest the presence of allergic disease.

 

Levels greater than the mean +2 SD strongly suggest the presence of allergic disease.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Specific IgE:

Testing for IgE antibodies is not useful in patients previously treated with immunotherapy to determine if residual clinical sensitivity exists, or in patients in whom the medical management does not depend upon identification of allergen specificity.

 

Some individuals with clinically insignificant sensitivity to allergens may have measurable levels of IgE antibodies in serum, and results must be interpreted in the clinical context.

 

False-positive results for IgE antibodies may occur in patients with markedly elevated serum IgE (>2,500 kU/L) due to nonspecific binding to allergen solid phases.

 

Total IGE:

The probability of finding an increased level of IgE in serum in a patient with allergic disease varies directly with the number of different allergens to which the patient is sensitized.

 

A normal level of IgE in serum does not eliminate the possibility of allergic disease.

 

Normal levels of IgE in serum occur in some patients with allergic disease, especially if there is sensitivity to a limited number of allergens and limited end organ involvement.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

 Specific IgE:

Class

IgE kU/L

Interpretation

0

<0.35

Negative

1

0.35-0.69

Equivocal

2

0.70-3.49

Positive

3

3.50-17.4

Positive

4

17.5-49.9

Strongly positive

5

50.0-99.9

Strongly positive

6

> or =100

Strongly positive

Reference values apply to all ages.

 

Total IgE:

Results Reported in kU/L

Age

Mean

+1SD

+2SD

0-6 weeks

0.6

2.3

8.8

7 weeks-3 months

1.0

4.1

17.0

4-6 months

1.8

7.3

30.0

7-9 months

2.6

10.0

39.0

10-23 months

3.2

13.0

53.0

2 years

5.7

23.0

93.0

3 years

8.0

32.0

128.0

4 years

10.0

40.0

160.0

5 years

12.0

48.0

192.0

6 years

14.0

56.0

224.0

7 years

16.0

63.0

248.0

8 years

18.0

71.0

280.0

9 years

20.0

78.0

304.0

10 years

22.0

85.0

328.0

Adults

13.2

41.0

127.0

Clinical References Provides recommendations for further in-depth reading of a clinical nature

Homburger HA: Allergic diseases. In Clinical Diagnosis and Management by Laboratory Methods. 21st edition. New York, WB Saunders Company, 2007, pp 961-971


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