Siemens IMMULITE 2000 Mode D'emploi page 5

Limitations
Patients on hGH therapy may develop
human antibodies to hGH that will interfere
in the assay and cause falsely low values.
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 ng/mL. (Unless
otherwise noted, all were generated on
serum samples collected in tubes without
gel barriers or clot-promoting additives.)
Conversion Factor:
ng/mL  3.0  mIU/L
WHO NIBSC 2nd IS 98/574
Reportable Range: 0.05 to 40 ng/mL
(0.15–120 mIU/L) WHO NIBSC 2nd IS
98/574
Analytical Sensitivity: 0.01 ng/mL
High Dose Hook Effect: None up to
17,000 ng/mL
Precision: Five samples were processed
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. (See "Linearity" table for
representative data.)
Recovery: Samples spiked 1 to 19 with
three hGH solutions (120, 240 and
480 ng/mL) were assayed. (See
"Recovery" table for representative data.)
IMMULITE 2000 Growth Hormone (hGH) (PIL2KGRH-11, 2018-03-15)
Specificity: The antibody is highly specific
for human growth hormone. (See
"Specificity" table.)
Bilirubin: Presence of conjugated and
unconjugated bilirubin in concentrations
up to 200 mg/L has no effect on results,
within the precision of the assay.
Biotin: Specimens that contain biotin at a
concentration of 1500 ng/mL demonstrate
a less than or equal to 10% change in
results. Biotin concentrations greater than
this may lead to incorrect results for
patient samples.
Hemolysis: Presence of hemoglobin in
concentrations up to 512 mg/dL has no
effect on results, within the precision of the
assay.
Lipemia: Presence of triglycerides in
concentrations up to 3000 mg/dL has no
effect on results, within the precision of the
assay.
Alternate Sample Type: To assess the
effect of alternate sample types, blood
was collected from 20 volunteers into
plain, heparinized, EDTA and Becton
®
Dickinson SST vacutainer tubes. Equal
volumes of the matched samples were
spiked with various concentrations of
hGH, to obtain values throughout the
reportable range of the assay, and then
assayed by the IMMULITE 2000 Growth
Hormone procedure.
(Heparin) = 0.99 (Serum) + 0.07 ng/mL
r = 0.997
(EDTA) = 1.0 (Serum) – 0.01 ng/mL
r = 0.997
(SST) = 0.98 (Plain Tubes) + 0.02 ng/mL
r = 0.999
Means:
4.15 ng/mL (Heparin)
4.12 ng/mL (EDTA)
4.14 ng/mL (Serum)
4.09 ng/mL (SST)
Method Comparison: The assay was
compared to IMMULITE Growth Hormone
(LKGRH, WHO NIBSC 2
72 samples. (Concentration range:
approximately 0.1 to 28 ng/mL. See
graph.) By linear regression:
(IML 2000) = 1.03 (IML) + 0.06 ng/mL
r = 0.997
Means:
6.75 ng/mL (IMMULITE 2000)
6.48 ng/mL (IMMULITE)
nd IS 98/574) on
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