• Component Description
• Eligible Sample
• Description of Laboratory Methodology
• Data Processing and Editing
• Laboratory Quality Assurance and Monitoring
• Analytic Notes
• Codebook
  • SEQN - Respondent sequence number
  • LBDHDD - Direct HDL-Cholesterol (mg/dL)
  • LBDHDDSI - Direct HDL-Cholesterol (mmol/L)

National Health and Nutrition Examination Survey

2009-2010 Data Documentation, Codebook, and Frequencies

Cholesterol - HDL (HDL_F)

Data File: HDL_F.xpt

First Published: September 2011

Last Revised: NA

Component Description

The data will be used to monitor the status of hyperlipidemia and the success of the National Cholesterol Education Program.

The main element of the cardiovascular disease laboratory component in NHANES is blood lipid levels. Cardiovascular disease is the leading cause of death in the United States. The data will be used to monitor the status of hyperlipidemia and the success of the National Cholesterol Education Program.

Eligible Sample

Participants aged 6 years and older were tested.

Description of Laboratory Methodology

Serum specimens were processed, stored, and shipped to University of Minnesota, Minneapolis, MN for analysis.

In this method a magnesium/dextran sulfate solution is first added to the specimen to form water-soluble complexes with non-HDL cholesterol fractions. These complexes are not reactive with the measuring reagents added in the second step. With addition of reagent 2, HDL-cholesterol esters are converted to HDL-cholesterol by PEG-cholesterol esterase. The HDL-cholesterol is acted upon by PEG-cholesterol oxidase, and the hydrogen peroxide produced from this reaction combines with 4-amino-antipyrine and HSDA under the action of peroxidase to form a purple/blue pigment that is measured photometrically at 600 nm (secondary wavelength = 700 nm). When the cholesterol measuring enzymes are modified with PEG, they are preferentially more reactive with HDL-cholesterol than the other cholesterol fractions. This is an endpoint reaction that is specific for HDL-cholesterol. This 3rd generation method differs from 2nd generation assays in the type of buffer used in the reagents, and the concentration of the reagent components. The basic reaction principle is unchanged.

There were no changes (from the previous 2 years of NHANES) to equipment, and lab site. The lab method was essentially the same. Read the following for these changes:

Detailed specimen collection and processing instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM).

Data Processing and Editing

Read the General Documentation on Laboratory Data file for detailed data processing and editing protocols. The analytical methods are described in the Description of Laboratory Methodology section above.

One derived variable was created in this data file. The formula for its derivation is as follows:

LBXHDD and LBDHDDSI:
The HDL-cholesterol in mg/dL (LBXHDD) was converted to mmol/L (LBDHDDSI) by multiplying by 0.02586.

Laboratory Quality Assurance and Monitoring

The NHANES quality assurance and quality control (QA/QC) protocols meet the 1988 Clinical Laboratory Improvement Amendments mandates. Detailed QA/QC instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM). Read the detailed QA/QC protocols in the General Documentation of Laboratory Data.

Analytic Notes

NHANES Survey Design:

The analysis of NHANES laboratory data must be conducted with the key survey design and basic demographic variables. The Household Questionnaire Data Files contain demographic data, health indicators, and other related information collected during household interviews. The Household Questionnaire Data Files also contain all survey design variables and sample weights required to analyze these data. The Phlebotomy Examination file includes auxiliary information on duration of fasting, the time of day of the venipuncture, and the conditions precluding venipuncture. The Household Questionnaire and Phlebotomy Examination files may be linked to the laboratory data file using the unique survey participant identifier SEQN.

Exam sample weights should be used for analyses. Please refer to the NHANES Analytic Guidelines and the on-line NHANES Tutorial  for further details on the use of sample weights and other analytic issues.

Codebook and Frequencies