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FREQUENTLY ASKED QUESTIONS

Why should my lab enroll in the LSP?

The LSP can ensure that lipid and lipoprotein measurements are accurate and comparable across long-term clinical trials and cardiovascular disease-related studies.

The primary objective of the CDC-NHLBI LSP is to provide laboratories with the opportunity to standardize their analysis of total cholesterol (TC), triglyceride (TG), and high-density lipoprotein cholesterol (HDL-C). Standardization ensures that the results of all clinical trials and population studies are comparable and traceable to well-defined standards.

Which labs should enroll in the LSP?

The CDC-NHLBI LSP is available to the following types of US and international laboratories:

1. Laboratories supporting epidemiologic studies and clinical trials
2. Lipid research laboratories
3. State/local public health laboratories
4. Reference laboratories
5. International lipid laboratories supporting epidemiologic and clinical trials of interest to NHLBI and the World Health Organization (WHO)

How can my laboratory enroll in the LSP?

Request an application packet from CDC and submit the completed application for approval. CDC will provide a qualifying survey to accepted laboratories to begin the standardization process. Please contact us for more information.

Are any fees associated with participation in the LSP?

There is no cost for the serum-based materials, assessments and evaluations, or consultations and technical assistance provided by CDC. The only cost to the participant is for shipping CDC's reference materials. Enrolled laboratories must provide a valid billing account number for a shipping courier (transporter) to CDC with the application enrollment packet.

What are CDC's reference materials?

CDC reference materials are prepared from human serum according to guideline C37-A (Preparation and Validation of Commutable Frozen Human Serum Pools as Secondary Reference Materials for Cholesterol Measurement Procedures; Approved Guideline (6) from the Clinical and Laboratory Standards Institute (CLSI - formerly the National Committee on Clinical Laboratory Standards, or NCCLS) (5). Portions of the sterile, filtered serum are dispensed into glass vials, which are sealed and frozen at -70° C.

What methods constitute the accuracy base for lipids and lipoproteins?

The National Cholesterol Education Program (NCEP) has recommended that CDC reference methods be used as the accuracy base for measuring total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides. The Abell-Kendall (AK) reference method for cholesterol (the AK method) and the ultracentrifugation method for HDL cholesterol have been accepted as reference measurement procedures of higher order by the Joint Committee for Traceability in Laboratory Medicine. The AK method is the basis for quantification of cholesterol in the reference methods for HDL cholesterol and LDL cholesterol.

Does participation in the LSP satisfy the federal regulatory requirements as stated in the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88)?

No, participation in the LSP does not satisfy CLIA-88 requirements for testing of total cholesterol, HDL cholesterol, and triglycerides. The LSP is not a Centers for Medicare & Medicaid Services (CMS)-approved proficiency testing (PT) provider. Although peer-group comparisons, such as the College of American Pathologists (CAP) surveys, do meet federal regulatory requirements for clinical labs, these surveys do not provide the same information that the LSP provides to laboratories supporting clinical trials and epidemiologic studies. The LSP is an accuracy-based program using commutable testing materials (16, 17).

What are matrix effects?

A matrix effect is the influence of a property of the sample, independent of the presence of the analyte, on the measurement and thereby on the value of the measurable quantity of that analyte. For instance, lipoprotein complexes modified during preparation and/or storage of reference materials can produce a different measurement signal than what would otherwise be expected from the native form of the analyte (15, 16, 17, 18).

What is a qualifying survey?

A qualifying survey is the initial survey designed for newly enrolled labs to begin their standardization process. Once the required performance criteria have been satisfied, the laboratory can proceed to the LSP monitoring survey.

Criteria for Acceptable Performance for the CDC-NHLBI Lipid Standardization Program Expressed in mg/dL

Analyte	Concentration Range of CDC Pool	Maximum Allowable Bias	Maximum Allowable Standard Deviation
HDLC	<40.0 ≤40.0	0.05 (RV) 0.05 (RV)	1.7 0.04 (RV)
TC	100-149.9 >149.9	0.03 (RV) 0.03 (RV)	4.0 0.03
TG	0.0-88.0 >88-176.0 >176.0-220.0 >220	9 10 11 0.05 (RV)	7 8 10 0.05 (RV)

Criteria for Acceptable Performance for the CDC-NHLBI Lipid Standardization Program Expressed in mmol/L

Analyte	Concentration Range of CDC Pool	Maximum Allowable Bias	Maximum Allowable Standard Deviation
HDLC (mmol/L)	<1.03 ≥1.03	0.05 (RV) 0.05 (RV)	0.0440 0.04 (RV)
TC (mmol/L)	2.586-3.877 >3.877	0.03 (RV) 0.03 (RV)	0.103 0.03 (RV)
TG (mmol/L)	0.00-0.994 >0.994-1.989 >1.989-2.486 >2.486	0.102 0.113 0.124 0.05 (RV)	0.079 0.090 0.113 0.05 (RV)

What is a monitoring survey?

A monitoring survey is the regularly scheduled LSP quarterly survey designed to assess and evaluate a laboratory's long-term lipid and lipoprotein measurement performance.

If my laboratory uses more than one analytical system to measure lipid and lipoprotein study samples, will these systems need to be standardized separately?

Yes. All systems used to measure lipid and lipoprotein study samples must be standardized separately to qualify as "standardized systems."