Siemens IMMULITE 2000 Mode D'emploi page 4

Quality Control Samples: Use controls
or sample pools with at least two levels
(low and high) of calcitonin.
Follow government regulations or
accreditation requirements for quality
control frequency.
Expected Values
Serum samples from 120 male and 90
female subjects in apparent good health
were analyzed by the IMMULITE 2000
Calcitonin procedure
Males: Upper 95% range: 8.4 pg/mL
(2.46 pmol/L)
Absolute range: ND–18.2 pg/mL
(ND–5.33 pmol/L)
Females: Upper 95% range: 5.0 pg/mL
(1.46 pmol/L)
Absolute range: ND–11.5 pg/mL
(ND–3.36 pmol/L)
Limitations
Multiple forms of immunoreactive
calcitonin are present in the circulation of
healthy subjects, patients with medullary
thyroid carcinoma, and patients with other
malignancies. These different forms of
calcitonin (polymers and/or glycosylated
forms) can have molecular weights
varying from 3.4 to 70 KDa. Therefore,
samples may exhibit varied response in an
immunoassay and non-linear dilution.
Some healthy individuals may be
encountered who have elevated
immunoreactive calcitonin levels.
Because calcitonin is highly labile, special
attention must be paid to proper specimen
collection and preservation.
Where several samples are collected from
a single patient, e.g. in pentagastrin
stimulation testing or serial monitoring, all
samples should be assayed by the same
procedure.
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
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24-28
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1,3,7
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 pg/mL. (Unless
otherwise noted, all were generated on
serum samples collected in tubes without
gel barriers or clot-promoting additives.)
Conversion Factor:
pg/mL  0.2926  pmol/L
Reportable Range: 2–2000 pg/mL
(WHO 2nd IRP 89/620)
High-dose Hook Effect:
None up to 25,000 pg/mL
Analytical Sensitivity: 2 pg/mL
(0.6 pmol/L)
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. (See "Linearity" table for
representative data.)
Recovery: Samples spiked 1 to 19 with
three calcitonin solutions (600, 6000 and
18,000 pg/mL) were assayed. (See
"Recovery" table for representative data.)
Specificity: The antibody is highly specific
for calcitonin. (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.
IMMULITE 2000 Calcitonin (PIL2KCL-18, 2018-03-15)