N,N-diethyl-3-methylbenzamide, commonly known as DEET, has become a widely used insect repellent in the United States. DEET is highly effective against a broad spectrum of insect pests, including potential disease vectors, such as mosquitoes, biting flies, and ticks (CDC, 2015). More than 500 products are currently registered with the Environmental Protection Agency in a variety of liquids, lotions, gels, sprays, sticks, and impregnated materials with DEET concentrations ranging from 5 to 98% (EPA, 2017). Every year, approximately one-third of the U.S. population uses DEET-containing insect repellents (CDC, 2009), and exposure to DEET is widespread (Calafat et al., 2016). Urinary metabolites of DEET are more sensitive biomarkers of exposure than DEET itself; in fact, relying on DEET as an exposure biomarker can lead to exposure misclassification (Calafat et al., 2016; ATSDR, 2017).
Examined participants aged 3 to 5 years and a one-third subsample of examined participants aged 6 years and older were eligible.
This method uses 0.2 mL of urine, followed by extraction of the target compounds with solid phase extraction of the target compounds weak cation exchange. The target compounds are separated using reversed phase high performance liquid chromatography (HPLC), ionized and de-solvated using a heated electrospray ionization (HESI) probe, and filtered selectively by mass-to-charge ratios at unit resolution via mass spectrometry.
Refer to the Laboratory Method Files section for a detailed description of the laboratory methods used.
There were no changes to the lab equipment or lab site for this component in the NHANES 2017-2018 cycle. However, a new lab analyte 3-(Ethylcarbamoyl) benzoic acid was added. It was previously introduced as a surplus in 2015-2016 and can be found in SSDEET_I.
DEET Metabolite – Urine (August 2026)
Urine specimens
were processed, stored, and shipped to the Division of Laboratory Sciences,
National Center for Environmental Health, Centers for Disease Control and
Prevention, Atlanta, GA for analysis.
Detailed instructions on specimen collection and processing are discussed in the
NHANES
Laboratory Procedures Manual (LPM). Vials were stored under appropriate frozen (-30°C)
conditions until they were shipped to National Center for Environmental Health
for testing.
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.
Analytical Laboratories
NHANES uses several methods to monitor the quality of the analyses performed by the contract laboratories. In the MEC, these methods include performing blind split samples collected during “dry run” sessions. In addition, contract laboratories randomly perform repeat testing on 2% of all specimens.
NCHS developed and distributed a QC protocol for all CDC and contract laboratories, which outlined the use of Westgard rules (Westgard et al., 1981) when running NHANES specimens. Progress reports containing any problems encountered during shipping or receipt of specimens, summary statistics for each control pool, QC graphs, instrument calibration, reagents, and any special considerations are submitted to NCHS quarterly. The reports are reviewed for trends or shifts in the data. The laboratories are required to explain any identified areas of concern.
All QC procedures recommended by the manufacturers were followed. Reported results for all assays meet the Division of Laboratory Sciences’ QA/QC performance criteria for accuracy and precision, similar to the Westgard rules (Caudill et al., 2008).
The data were reviewed. Incomplete data or improbable values were sent to the performing laboratory for confirmation.
Refer to the 2017-2018 Laboratory Data Overview for general information on NHANES laboratory data.
There are over 800 laboratory tests performed on NHANES participants. However, not all participants provided biospecimens or enough volume for all the tests to be performed. The specimen availability can also vary by age or other population characteristics. Analysts should evaluate the extent of missing data in the dataset related to the outcome of interest as well as any predictor variables used in the analyses to determine whether additional re-weighting for item non-response is necessary.
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.
Subsample weights
DEET metabolites were measured in a one-third subsample of participants 6 years and older. Special sample weights are required to analyze these data properly. Specific sample weights for this subsample are included in this data file and should be used when analyzing these data.
Demographic and Other Related Variables
The analysis of NHANES laboratory data must be conducted using the appropriate survey design and demographic variables. The NHANES 2017-2018 Demographic 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
The detection limits were constant for all of the analytes in the data set. Two variables are provided for each of these analytes. The variable name ending in “LC” (ex., URDDEALC) indicates whether the result was below the limit of detection: the value “0” means that the result was at or above the limit of detection, “1” indicates that the result was below the limit of detection. The other variable prefixed URX (ex., URXDEA) provides the analytic result for that analyte. For analytes with analytic results below the lower limit of detection (i.e., URDDEALC=1), an imputed fill value was placed in the analyte results field. This value is the lower limit of detection divided by square root of 2 (LLOD/sqrt [2]).
The lower limit of detection (LLOD in ng/mL) for DEET metabolite is:
| Variable Name | Analyte Description | LLOD |
|---|---|---|
| URXDEA | 3-(diethylcarbamoyl) benzoic acid (DEET acid) (ug/L) | 0.1 |
| URXMEA | 3-(Ethylcarbamoyl) benzoic acid (MEA) (ug/L) | 0.1 |
| Code or Value | Value Description | Count | Cumulative | Skip to Item |
|---|---|---|---|---|
| 3829.845402 to 1395405.4654 | Range of Values | 2851 | 2851 | |
| 0 | No Lab Result | 135 | 2986 | |
| . | Missing | 0 | 2986 |
| Code or Value | Value Description | Count | Cumulative | Skip to Item |
|---|---|---|---|---|
| 0.0707 to 19700 | Range of Values | 2808 | 2808 | |
| . | Missing | 178 | 2986 |
| Code or Value | Value Description | Count | Cumulative | Skip to Item |
|---|---|---|---|---|
| 0 | At or above detection limit | 2587 | 2587 | |
| 1 | Below lower detection limit | 221 | 2808 | |
| . | Missing | 178 | 2986 |
| Code or Value | Value Description | Count | Cumulative | Skip to Item |
|---|---|---|---|---|
| 0.0707 to 6120 | Range of Values | 2804 | 2804 | |
| . | Missing | 182 | 2986 |
| Code or Value | Value Description | Count | Cumulative | Skip to Item |
|---|---|---|---|---|
| 0 | At or above the detection limit | 2352 | 2352 | |
| 1 | Below lower detection limit | 452 | 2804 | |
| . | Missing | 182 | 2986 |