Table of Contents

Component Description

The dual energy x-ray absorptiometry (DXA) scan was performed on survey participants 8 years and older. The scan involves radiation exposure to the whole body. Pregnant women are excluded from the DXA, bioelectrical impedance, and cardiovascular fitness components of the mobile examination center, so a urine pregnancy test was performed first. If the urine test results were positive for pregnancy, a serum pregnancy test was also performed.

Eligible Sample

A pregnancy test was completed on female participants aged 12–59 years and menstruating females aged 8–11 years.

Description of Laboratory Methodology

The Icon 25 hCG test kit (Beckman Coulter) is a rapid chromatographic immunoassay for the qualitative detection of human chorionic gonadotropin (hCG) in urine or serum to aid in the early detection of pregnancy. The test utilizes a combination of monoclonal and polyclonal antibodies to selectively detect elevated levels of hCG in urine or serum.

A detailed description of the laboratory method used can be found on the NHANES website.

Data Processing and Editing

Urine and serum specimens were tested in the NHANES mobile examination centers. Detailed specimen collection and processing instructions are discussed in the NHANES LPM.

Detailed instructions on specimen collection and processing can be found on the NHANES website.

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). Read the LABDOC file for detailed QA/QC protocols.

A detailed description of the quality assurance and quality control procedures can be found on the NHANES website.

Analytic Notes

A pregnancy test was completed on female participants aged 12–59 years and menstruating females aged 8–11 years.

Codebook and Frequencies

SEQN - Respondent sequence number

Variable Name:
SEQN
SAS Label:
Respondent sequence number
English Text:
Respondent sequence number.
Target:
Females only 8 YEARS - 59 YEARS

URXPREG - Pregnancy test result

Variable Name:
URXPREG
SAS Label:
Pregnancy test result
English Text:
Pregnancy test result
English Instructions:
The test is done on females 8-11 who have started menstruating and all females 12-59 years.
Target:
Females only 8 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 None 3 3
1 Positive 269 272
2 Negative 2380 2652
3 Not done 51 2703
4 Invalid 1 2704
. Missing 0 2704