Performance Data - Siemens IMMULITE 2000 C-Peptide Mode D'emploi

roughly five times that of insulin, even
though the two molecules are secreted in
an equimolar ratio. Again, the liver plays a
major role in clearing insulin, whereas
C-peptide is removed by degradation and
elimination mainly through the kidneys.
Hepatic and renal complications will
therefore affect the circulating
C-peptide/insulin ratio.
Heterophilic antibodies in human
serum/plasma 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 Factors:
ng/mL × 0.331  nmol/L
ng/mL × 331  pmol/L
Reportable Range: 0.1 – 20 ng/mL
(0.03 – 6.6 nmol/L;
33 – 6,620 pmol/L).
Standardized to WHO 1st IRP 84/510.
Analytical Sensitivity:
Limit of Blank (highest value expected for a
sample with no analyte; determined in
accordance with CLSI EP17-A
0.05 ng/mL (0.02 nmol/L, 17 pmol/L)
Limit of Detection (lowest detectable
concentration; determined in accordance
13
with CSLI EP17-A
0.08 ng/mL (0.03 nmol/L, 27 pmol/L)
IMMULITE 2000 C-Peptide (PIL2KPEP-9, 2018-03-15)
13
):
):
Functional Sensitivity: (concentration with
20% coefficient of variation (CV)
determined in accordance with CLSI EP17-
13
A and CLSI EP5-A2
0.08 ng/mL (0.03 nmol/L, 27 pmol/L)
High Dose Hook Effect: None up to
3,560 ng/mL
Precision: Samples were assayed in
duplicate over the course of 10 days, four
runs per day, for a total of 40 runs and 80
replicates. (See "Precision" table.)
Linearity: Serums samples were assayed
under various dilutions. (See "Linearity"
table for representative data.)
Recovery: Serum samples spiked 1 to 19
with three C-peptide solutions (23, 50 and
107 ng/mL) were assayed. (See
"Recovery" table for representative data.)
Specificity: The antibody is highly specific
for C-peptide. (See "Specificity" table.)
Bilirubin: Presence of conjugated and
unconjugated bilirubin in concentrations
up to 200 mg/L may cause a depression
of values (See "Bilirubin" tables).
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 500 mg/dL has no
effect on results, within the precision of the
assay.
Lipemia: Presence of triglycerides in
concentrations up to 3,000 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 volunteers into plain,
heparinized plasma, Becton Dickinson
 
SST and PST vacutainer tubes. Some
samples were spiked with C-peptide to
provide values throughout the reportable
range of the assay. All samples were
assayed by the IMMULITE 2000 C-
Peptide procedure, with the following
results.
(Heparin) = 0.93 (Serum) + 0.67 ng/mL
r = 0.99
n = 43
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):
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