• Component Description
• Eligible Sample
• Description of Laboratory Methodology
• Data Processing and Editing
• Laboratory Quality Assurance and Monitoring
• Analytic Notes
• Codebook
  • SEQN - Respondent sequence number
  • LB2DAY - Days betwen first and second exams
  • LB2P1 - PSA. total (ng/mL)
  • LB2P2 - PSA, free (ng/mL)
  • LB2P3 - Prostate specific antigen ratio (%)

National Health and Nutrition Examination Survey

2001-2002 Data Documentation, Codebook, and Frequencies

Prostate-specific Antigen (PSA), Second Exam (l11p_2_b)

Data File: l11p_2_b.xpt

First Published: July 2010

Last Revised: NA

Component Description

Free Prostate-specific Antigen (P1), Total Prostate-specific Antigen (P2): Total and free Prostate-specific antigens (PSA) were measured among men age 40-69 years. PSA immunoassay was performed on blood specimens using the Hybritech tests (Beckman Coulter, Fullerton, CA).

See the general documentation on Second Day laboratory exams.  Also, see the documentation for the primary exam data for Lab 11 PSA.

Eligible Sample

Male participants aged 40-69 years were tested for PSA.

Description of Laboratory Methodology

Free Prostate-specific Antigen (LB2P1):
The Access Hybritech free PSA assay is a two-site immunoenzymatic "sandwich" assay. A sample was added to a reaction vessel with mouse monoclonal anti-free PSA alkaline phosphatase conjugate, and paramagnetic particles coated with a second mouse monoclonal anti-free PSA antibody. The free PSA in the sample bound to the immobilized monoclonal anti-free PSA on the solid phase while, at the same time, the monoclonal anti-PSA conjugate reacted with a different antigenic site on the sample free PSA. Separation in a magnetic field and washing removes material not bound to the solid phase. A chemiluminescent substrate, Lumi-Phos^tm 530 was added to the reaction vessel and light generated by the reaction was measured with a luminometer. The light production was proportional to the concentration of free PSA in the sample. The amount of analyte in the sample was determined by means of a stored, multi-point calibration curve.

Total Prostate- specific Antigen (LB2P2): 
Total PSA values were obtained using the Hybritech PSA method on the Beckman Access. A second sample was added to a reaction vessel with mouse monoclonal anti-PSA alkaline phosphatase conjugate and paramagnetic particles coated with a second mouse monoclonal anti-PSA antibody. The PSA in the sample bound to the immobilized monoclonal anti-PSA on the solid phase while, at the same time, the monoclonal anti-PSA conjugate reacted with a different antigenic site on the sample PSA. The light production was proportional to the concentration of PSA in the sample..

Prostate-specific Antigen ratio (LB2P3): 
This ratio was calculated by dividing the free PSA (P1) by the total PSA (P2):
LB2P3 = round ((LB2P2/LB2P1)*100))

 

Data Processing and Editing

Specimens were processed, stored and shipped to University of Washington, Seattle, Washington. Detailed specimen collection and processing instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM). Read the LABDOC file for detailed data processing and editing protocols. The analytical methods are described in the Description of Laboratory Methodology section.

Laboratory Quality Assurance and Monitoring

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

Analytic Notes

All data are publicly available.

The second day exam data was a convenience sample and thus did not have sample weights. The analysis of NHANES laboratory data must be conducted with the key survey design and basic demographic variables. The NHANES Questionnaire Data Files contain demographic data, health indicators, and other related information collected during household interviews. The Phlebotomy Examination File includes auxiliary information such 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.

Data on health conditions that would make a sample person ineligible for PSA testing are missing for some people (n=60) with non-missing PSA lab data. This happened mainly because some sample persons did not attend the physician’s examination component of the MEC examination where such data were collected. It is advisable to exclude these observations for PSA analyses.

Codebook and Frequencies