Performance Data - Siemens IMMULITE 2000 Total IgE Manual Del Usuario

Consider these limits as guidelines only.
Each laboratory should establish its own
reference ranges.
Limitations
Serum total IgE levels for the majority of
individuals with IgE-mediated disease can
be expected to be elevated compared to
the reference range for healthy adults.
However, not all allergic patients exhibit
elevated serum total IgE levels.
Since not all atopic reactions are IgE-
mediated, a total IgE result in the
reference range should always be
interpreted in light of other clinical
observations.
Tests for allergen-specific IgE may clarify
the finding of an elevated total IgE result.
Heterophilic antibodies in human serum
can react with the immunoglobulins
included in the assay components causing
interference with in vitro immunoassays.
[See Boscato LM, Stuart MC. Heterophilic
antibodies: a problem for all
immunoassays. Clin Chem 1988:34:27-
33.] Samples from patients routinely
exposed to animals or animal serum
products can demonstrate this type of
interference potentially causing an
anomalous result. These reagents have
been formulated to minimize the risk of
interference; however, potential
interactions between rare sera and test
components can occur. For diagnostic
purposes, the results obtained from this
assay should always be used in
combination with the clinical examination,
patient medical history, and other findings.

Performance Data

See Tables and Graphs for data
representative of the assay's performance.
Results are expressed in IU/mL. (Unless
otherwise noted, all were generated on
serum samples collected in tubes without
gel barriers or clot-promoting additives.)
Conversion Factor:
IU/mL × 2.4 → ng/mL
IU/mL × 1 → kIU/L
Calibration Range: up to 2,000 IU/mL.
Standardized in reference to WHO 2nd
IRP 75/502.
Analytical Sensitivity: 1.0 IU/mL.
4
High-dose Hook: No effect up to
13,000 IU/mL.
Precision: Samples were assayed in
duplicate over the course of 20 days, two
runs per day, for a total of 40 runs and 80
replicates. (See "Precision" table.)
Linearity: Samples were assayed under
various dilutions. The results show that the
IMMULITE 2000 Total IgE kit maintains
good linearity throughout its calibration
11
range; but due to the heterogeneity of
circulating IgE with different affinities,
there may be a loss of dilutional
parallelism in certain patients. (See
"Linearity" table for representative data.)
Recovery: Samples spiked 1 to 19 with
three total IgE solutions (1,750, 3,500 and
7,000 IU/mL) were assayed. (See
"Recovery" table for representative data.)
Specificity: The assay is highly specific for
human IgE and exhibits no crossreactivity
to other human immunoglobulin classes.
Bilirubin: Presence of bilirubin in
concentrations up to 200 mg/L has no
effect on results, within the precision of the
assay.
Hemolysis: Presence of hemoglobin in
concentrations up to 384 mg/dL has no
effect on results, within the precision of the
assay.
Lipemia: Presence of triglycerides in
concentrations up to 5,000 mg/dL has no
effect on results, within the precision of the
assay.
Method Comparison: The assay was
compared to IMMULITE Total IgE on 175
samples. (Concentration range:
approximately 2 to 1,600 IU/mL. See
graph.) By linear regression:
(IML 2000) = 0.96 (IML) + 10.0 IU/mL
r = 0.988
Means:
225 IU/mL (IMMULITE 2000)
223 IU/mL (IMMULITE)
References
1) Barbee RA, et al. Distribution of IgE in a
community population sample: correlation with
age, sex and allergen skin test reactivity. J
Allergy Clin Immunol 1981;68:106–11. 2) Geha
RS. Human IgE. J Allergy Clin Immunol
1984;74:109–20. 3) Gordon RR, et al.
Immunoglobulin E and the eczema-asthma
syndrome in early childhood. Lancet 1982;1:72–
74. 4) Halpern GM. Markers of human allergic
IMMULITE 2000 Total IgE (PIL2KIE-18, 2006-12-29)