The phlebotomy component of NHANES involved the collection of blood specimens. Prior to blood collection, the MEC phlebotomist administered a questionnaire to screen for conditions that would exclude participants from the blood draw. At this time, fasting status was determined. Blood specimens for basic hematology, nutritional biochemistry, and special studies were obtained.
Blood specimens were collected on participants aged one year and older in the Mobile Examination Center (MEC).
Participants aged 1 year and older were tested.
Description of Laboratory Methodology
The MEC phlebotomist drew blood from the participant’s arm. Participants with hemophilia or who received cancer chemotherapy in the past four weeks or will receive it in the future four weeks were excluded from the venipuncture.
Data Processing and Editing
Phlebotomy data were recorded directly into a computerized database; all forms used in the MEC were automated. Detailed phlebotomy collection and processing instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM).
Laboratory Quality Assurance and Monitoring
The NHANES quality control and quality assurance protocols (QA/QC) meet the 1988 Clinical Laboratory Improvement Act mandates. Detailed quality control and quality assurance instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM).
The analysis of NHANES 2003-2004 laboratory data must be conducted with the key survey design and basic demographic variables. The NHANES 2003-2004 Household Questionnaire Data Files contain demographic data, health indicators, and other related information collected during household interviews. They also contain all survey design variables and sample weights for these age groups. The phlebotomy file includes auxiliary information such as the conditions precluding venipuncture. The household questionnaire and phlebotomy files may be linked to the laboratory data file using the unique survey participant identifier SEQN.
Use PHAFSTHR and PHAFSTMN to determine the duration of fasting in hours and minutes, respectively.
Use PHDSESN to determine the session in which the participant was examined.