Siemens IMMULITE 2000 C-Peptide Mode D'emploi page 2

IMMULITE
English
Intended Use: For in vitro diagnostic use
with the IMMULITE 2000 Systems
Analyzers — for the quantitative
measurement of C-peptide in serum,
heparinized plasma, or urine, as an aid in
the diagnosis and treatment of patients
with abnormal insulin secretion.
Catalog Number: L2KPEP2 (200 tests),
Test Code: PEP Color: Dark Blue
Summary and Explanation
Human C-peptide is a 31 amino acid chain
with a molecular mass of approximately
3,020 daltons. Metabolically inert, it
originates in the pancreatic -cells as a by-
product of the enzymatic cleavage of
1,2,5
proinsulin to insulin.
insulin and C-peptide are split from the
prohormone and secreted into the portal
circulation in equimolar concentrations.
is this fact which underlies the clinical interest
in plasma determinations of C-peptide.
Within limits, C-peptide levels can serve as
a valuable index to insulin secretion. Thus,
low C-peptide levels are to be expected
where insulin secretion is diminished, as in
insulin-dependent diabetes, or suppressed,
as a normal response to exogenous insulin;
whereas elevated C-peptide levels may
result from the increased -cell activity
observed in insulinomas.
Accordingly, in the differential diagnosis of
hypoglycemia, C-peptide determinations
can be used to supplement insulin
measurements as an index to pancreatic
activity in the classic 72-hour fasting test,
and as the sole indicator of pancreatic
activity where insulin itself is administered
to check for suppressibility.
covert self-administration of insulin can be
virtually ruled out as the cause of
hyperinsulinemia by the finding of an
elevated C-peptide level.
Circulating anti-insulin antibodies are
commonly encountered in patients who
have undergone insulin therapy. These
would typically interfere with immunoassays
for insulin, making it impossible to use
2
2000 C-Peptide
®
In this process,
4,5,7 It
3,4,6,9
1,8
In addition,
2,3,8,9
insulin measurements in this context to
check on residual -cell activity, even if
treatment were temporarily suspended.
C-peptide measurements have therefore
been used as an alternative in this context,
to yield information on the natural history of
insulin-dependent diabetes, to indirectly
monitor insulin secretion in the presence of
anti-insulin antibodies, and to help settle on
an appropriate course of treatment.
C-peptide has also been measured as an
additional means for evaluating glucose
tolerance and glibenclamide-glucose
2,3,10
tests.
Principle of the Procedure
IMMULITE 2000 C-Peptide is a solid-
phase, two-site chemiluminescent
immunometric assay. The solid phase
(bead) is coated with monoclonal murine
anti-C-peptide antibody. The liquid phase
consists of alkaline phosphatase (bovine
calf intestine) conjugated to monoclonal
murine anti-C-peptide antibody in buffer.
The patient sample and the reagent are
incubated together with the coated bead
for 30 minutes. During this time, C-peptide
in the sample forms the antibody sandwich
complex with monoclonal murine anti-
C-peptide antibody on the bead and
enzyme-conjugated monoclonal murine
anti-C-peptide antibody in the reagent.
Unbound patient sample and enzyme
conjugate are then removed by centrifugal
washes. Finally, chemiluminescent
substrate is added to the reaction tube
containing the bead and the signal is
generated in proportion to the bound
enzyme.
Incubation Cycles: 1 × 30 minutes
Time to first result: 35 minutes.
Specimen Collection
Serum and Heparinized Plasma:
The patient should be fasting. Collect
blood by venipuncture,
hemolysis, into plain tubes (without
anticoagulant) or heparinized tubes,
noting the time of collection, and separate
the serum or plasma from the cells.
IMMULITE 2000 C-Peptide (PIL2KPEP-9, 2018-03-15)
3,6,7,10
12
avoiding