A urine pregnancy test was performed in the mobile examination center (MEC) on menstruating female survey participants 8 years and older. All positive test results excluded pregnant women from the DXA component at the MEC.
Examined female participants aged 12–59 years, and menstruating females aged 8–11 years were eligible. However, due to disclosure risks, only females 20-44 years of age have urine pregnancy results in this file.
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.
Refer to the Laboratory Methods Files section for a detailed description of the laboratory methods used.
There were no changes to the lab method, lab equipment, or lab site for this component in the NHANES 2021-2023 cycle.
Urine specimens were processed in the NHANES mobile examination centers.
Detailed instructions on specimen collection and processing are discussed in the NHANES Laboratory Procedures Manual (LPM).
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 LPM.
Mobile Examination Centers (MECs)
Laboratory team performance is monitored using several techniques. NCHS and contract consultants use a structured competency assessment evaluation during visits to evaluate both the quality of the laboratory work and the QC procedures. Each laboratory staff member is observed for equipment operation, specimen collection and preparation; testing procedures and constructive feedback are given to each staff member. Formal retraining sessions are conducted annually to ensure that required skill levels were maintained.
The data were reviewed. Incomplete data or improbable values were sent to the performing laboratory for confirmation.
Refer to the August 2021-August 2023 Laboratory Data Overview for general information on NHANES laboratory data.
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.
Demographic and Other Related Variables
The analysis of NHANES laboratory data must be conducted using the appropriate survey design and demographic variables. The NHANES August 2021- August 2023 Demographics File contains demographic data, health indicators, and other related information collected during household interviews as well as the sample design variables. The recommended procedure for variance estimation requires use of stratum and PSU variables (SDMVSTRA and SDMVPSU, respectively) in the demographic data file.
This laboratory data file can be linked to the other NHANES data files using the unique survey participant identifier (i.e., SEQN).
Detection Limits
Since this data is reported as qualitative data, the use of lower LLOD is not applicable.
| Code or Value | Value Description | Count | Cumulative | Skip to Item |
|---|---|---|---|---|
| 1 | Positive | 41 | 41 | |
| 2 | Negative | 1078 | 1119 | |
| 3 | Not Done | 11 | 1130 | |
| 4 | Invalid | 0 | 1130 | |
| . | Missing | 4 | 1134 |