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One
Page Summary
Cardiovascular
Disease
Background
Ensuring
reliable lipid measurements for the investigation of risk factors
associated with cardiovascular disease (CVD) and other related chronic
diseases, such as diabetes, in the U.S. population is a major
responsibility of (DLS).
DLS,
through the CDC, National Heart, Lung, and Blood Institute and the Lipid
Standardization Program (LSP), standardizes lipid research laboratories
that provide laboratory analyses for more than 100 federal- or
state-funded projects designed to investigate risk factors for cardiovascular and other related chronic diseases.
The
Lipid Standardization Program (LSP)
Standardization is a needed step in building an effective quality-assurance system in laboratory testing.
Quality laboratory performance (based on minimum performance
standards) must be established before maintenance and control of long term
quality laboratory testing can be ensured.
To fulfill its commitment to improve the measurement of risk factors associated with cardiovascular disease, DLS has focused
on: 1) maintaining the highest quality lipid reference
laboratory; and 2) offering standardization services through the LSP to
federally funded and other public health heart-disease epidemiologic and
research laboratories.
The goal of the LSP is to improve the
laboratory measurement of cholesterol, triglycerides, high-density
lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C)
so they are measured with the accuracy and precision needed to reliably
detect, treat, and prevent cardiovascular disease.
The LSP
differs from typical proficiency testing programs in
which clinical laboratories typically participate to meet federal
regulatory requirements -- such as the Clinical Laboratory Improvement
Amendments of 1988 (CLIA-88). The
LSP is designed to improve a laboratory’s analytical accuracy
and precision performance by standardizing results over time and
establishing a traceable link to the approved accuracy base at CDC. Proficiency testing programs, on the other hand, are based on
peer grouping and provide no mechanism for establishing, assessing or
improving accuracy. Such
programs can evaluate only how well a laboratory carries out analytical
testing in comparison to other laboratories using the same analytical
systems and are not able to establish traceability to an accepted accuracy
base.
The LSP
is a rigorous three-part process designed so that each participating
laboratory can achieve a standardized level of performance and validate
traceability to a common reference point maintained by CDC.
The standardization process requires laboratories to perform
multiple analyses of CDC frozen-serum lipid reference
materials that are prepared by pooling units from human donors
collected to give specific lipid-concentration limits.
The CDC
reference materials are provided to
the laboratory as “unknowns,” that is, the laboratory does not know
the value of the lipid concentrations in the samples.
Upon successfully completing all three
parts of the program, a laboratory is considered to be standardized for measurement of the specified lipids. To maintain standardization
performance, laboratories are monitored through quarterly
analyses of selected panels of CDC test samples.
The LSP provides standardization services to over 100 participating
laboratories, including international institutions.
The Cholesterol Reference Method Laboratory Network
(CRMLN)
certifies manufacturers of clinical diagnostic products that measure total
cholesterol, HDL-C, and LDL-C. The CRMLN laboratories
use reference methods or designated comparison methods that are rigorously
standardized to the CDC reference methods. The Food and Drug
Administration (FDA) has
recognized the value of the CRMLN's certification program for
manufacturers and now requests that all devices for measuring total
cholesterol, HDL-C and LDL-C be certified through the CRMLN.
DLS maintains the network. American Association for Clinical Chemistry
maintains a site that
lists the clinical diagnostic products that have been certified by the
CRMLN. The CRMLN also has a
program for certification of individual clinical laboratories measurement
of total cholesterol Contact
any of the CRMLN
laboratories for more information about this program
DLS has
also collaborated with the NCCLS to
develop written specifications (NCCLS C37-A) for preparing cholesterol reference
materials that have sufficient commutability for the standardization of
serum cholesterol measurements.
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