Table of Contents

Component Description

The NHANES program suspended field operations in March 2020 due to the coronavirus disease 2019 (COVID-19) pandemic. As a result, data collection for the NHANES 2019-2020 cycle was not completed and the collected data are not nationally representative. Therefore, data collected from 2019 to March 2020 were combined with data from the NHANES 2017-2018 cycle to form a nationally representative sample of NHANES 2017-March 2020 pre-pandemic data. These data are available to the public. Please refer to the Analytic Notes section for more details on the use of the data.

Exposure to volatile organic compounds (VOCs) is ubiquitous. Chronic exposure to extremely high levels of some VOCs can lead to cancer and neurocognitive dysfunction. Urinary metabolites of VOCs can be detectable in urine for a longer period of time than the parent VOCs can be detected in blood.

Nearly 200 air toxicants have been associated with adverse health effects in occupational studies or laboratory studies, but have not been monitored in general population groups. Information on levels of exposure to these compounds, as measured by their metabolite levels in urine, is essential to determine the need for regulatory mechanisms to reduce the levels of hazardous air pollutants to which the general population is exposed.

Eligible Sample

All examined participants aged 3 to 5 years and participants aged 6 years and older from a one-third subsample in the NHANES 2017-March 2020 pre-pandemic sample were eligible.

Description of Laboratory Methodology

This method is a quantitative procedure for the measurement of VOC metabolites in human urine using ultra performance liquid chromatography coupled with electrospray tandem mass spectrometry (UPLC-ESI/MSMS) as described by Alwis et al., (2012). Chromatographic separation is achieved using an Acquity UPLC® HSS T3 (Part no. 186003540, 1.8 µm x 2.1 mm x 150 mm, Waters Inc.) column with 15 mM ammonium acetate and acetonitrile as the mobile phases. The eluent from the column is ionized using an electrospray interface to generate and transmit negative ions into the mass spectrometer. Comparison of relative response factors (ratio of native analyte to stable isotope labeled internal standard) with known standard concentrations yields individual analyte concentrations.

Refer to the Laboratory Method Files section for a detailed description of the laboratory methods used.

Laboratory Method Files

Volatile Organic Compounds (VOCs) Metabolites (September 2022)

Volatile Organic Compounds (VOCs) Metabolites (September 2022)

Laboratory Quality Assurance and Monitoring

Urine specimens are 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 2017-2018 and 2019-2020 NHANES Laboratory Procedures Manuals (LPMs). Vials are stored under appropriate frozen (–30°C) conditions until they are 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 Amendment mandates. Detailed QA/QC instructions are discussed in the NHANES LPMs.

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 CDC and 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 testing 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).

Data Processing and Editing

The data were reviewed. Incomplete data or improbable values were sent to the performing laboratory for confirmation.

Analytic Notes

The COVID-19 pandemic required suspension of NHANES 2019-2020 field operations in March 2020 after data were collected in 18 of the 30 survey locations in the 2019-2020 sample. Data collection was cancelled for the remaining 12 locations. Because the collected data from 18 locations were not nationally representative, these data were combined with data from the previous cycle (2017-2018) to create a 2017-March 2020 pre-pandemic data file. A special weighting process was applied to the 2017-March 2020 pre-pandemic data file. The resulting sample weights in the demographic data file should be used to calculate estimates from the combined cycles. These sample weights are not appropriate for independent analyses of the 2019-2020 data and will not yield nationally representative results for either the 2017-2018 data alone or the 2019-March 2020 data alone. Please refer to the NHANES website for additional information for the NHANES 2017-March 2020 pre-pandemic data, and for the previous 2017-2018 public use data file with specific weights for that 2-year cycle.

Refer to the 2017-2018 and 2019-2020 Laboratory Data Overview documents 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

The analytes included in this dataset were measured in all examined participants aged 3-5 years, and in a one-third subsample of participants 6 years and older. Special sample weights are required to analyze these data properly. Variable (WTSAPRP) encoding of the specific sample weights for this subsample is included in this data file and should be used when analyzing these data. These special sample weights were created to account for the subsample selection probability, as well as the additional nonresponse to these lab tests. Therefore, if participants were eligible for the subsample, but did not provide a urine specimen, they would have the sample weight value assigned as “0” in their records.

Demographic and Other Related Variables

The analysis of NHANES laboratory data must be conducted the appropriate survey design and demographic variables. The NHANES 2017- March 2020 Pre-Pandemic 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

The detection limits were constant for the analytes in the data set. Two variables are provided for each of these analytes. The variable named ending in “LC” (ex., URDAAMLC) 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. For analytes with analytic results below the lower limit of detection (ex., URDAAMLC=1), an imputed fill value was placed in the analyte results field. This value is the lower limit of detection divided by the square root of 2 (LLOD/sqrt [2]). The other variable prefixed URX (ex., URXAAM) provides the analytic result for the analyte. All data are rounded to three significant figures or three decimal places, whichever is less precise.

The lower limit of detection (LLOD, in ng/mL) for urinary VOC metabolites:

VARIABLE NAME   ANALYTE NAME    LLOD 
URXAAM N-Acetyl-S-(2-carbamoylethyl)-L-cysteine (ng/mL) 2.20
URXAMC N-Acetyl-S-(N-methylcarbamoyl)-L-cysteine (ng/mL) 6.26
URXATC 2-Aminothiazoline-4-carboxylic acid (ng/mL) 29.5
URXBMA N-Acetyl-S-(benzyl)-L-cysteine (ng/mL) 0.500
URXBPM N-Acetyl-S-(n-propyl)-L-cysteine (ng/mL) 1.20
URXCEM N-Acetyl-S-(2-carboxyethyl)-L-cysteine (ng/mL) 6.96
URXCYHA N-Acetyl-S-(1-cyano-2-hydroxyethyl)-L-cysteine (ng/mL) 2.60
URXCYM N-Acetyl-S-(2-cyanoethyl)-L-cysteine (ng/mL) 0.500
URXDHB N-Acetyl-S-(3,4-dihydroxybutyl)-L-cysteine (ng/mL) 5.25
URXGAM N-Acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine (ng/mL) 9.40
URXHEM N-Acetyl-S-(2-hydroxyethyl)-L-cysteine (ng/mL) 0.791
URXHPM N-Acetyl-S-(3-hydroxypropyl)-L-cysteine (ng/mL) 13.0
URXHP2 N-Acetyl-S-(2-hydroxypropyl)-L-cysteine (ng/mL) 5.3
URXIPM3 N-Acetyl-S-(4-hydroxy-2-methyl-2-butenyl)-L-cysteine (ng/mL) 1.20
URXMAD Mandelic acid (ng/mL) 12.0
URX2MH 2-Methylhippuric acid (ng/mL) 5.00
URX34M 3- and 4-Methylhippuric acid (ng/mL) 8.00
URXMB3 N-Acetyl-S-(4-hydroxy-2-butenyl)-L-cysteine (ng/mL) 0.600
URXPHG Phenylglyoxylic acid (ng/mL) 12.0
URXPMM N-Acetyl-S-(3-hydroxypropyl-1-methyl)-L-cysteine (ng/mL) 1.70
URXTTC 2-Thioxothiazolidine-4-carboxylic acid 11.2

 

References

Codebook and Frequencies

SEQN - Respondent Sequence Number

Variable Name:
SEQN
SAS Label:
Respondent Sequence Number
English Text:
Respondent Sequence Number
Target:
Both males and females 3 YEARS - 150 YEARS

WTSAPRP - Subsample A Weights Pre-Pandemic

Variable Name:
WTSAPRP
SAS Label:
Subsample A Weights Pre-Pandemic
English Text:
Subsample A Weights Pre-Pandemic
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2395.195359 to 955677.30961 Range of Values 4727 4727
0 Participants 3+ years with no lab specimen 163 4890
. Missing 0 4890

URX2MH - 2-methylhippuric acid (ng/mL)

Variable Name:
URX2MH
SAS Label:
2-methylhippuric acid (ng/mL)
English Text:
2-methylhippuric acid (ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3.54 to 60300 Range of Values 4325 4325
. Missing 565 4890

URD2MHLC - 2-methylhippuric acid comment code

Variable Name:
URD2MHLC
SAS Label:
2-methylhippuric acid comment code
English Text:
2-methylhippuric acid comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 3818 3818
1 Below lower detection limit 507 4325
. Missing 565 4890

URX34M - 3-methipurc acd & 4-methipurc acd(ng/mL)

Variable Name:
URX34M
SAS Label:
3-methipurc acd & 4-methipurc acd(ng/mL)
English Text:
3-methylhippuric acid & 4-methylhippuric acid(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5.66 to 586000 Range of Values 4325 4325
. Missing 565 4890

URD34MLC - 3-methipurc acd & 4-methipurc acid comt

Variable Name:
URD34MLC
SAS Label:
3-methipurc acd & 4-methipurc acid comt
English Text:
3-methylhippuric acid & 4-methylhippuric acid comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 4296 4296
1 Below lower detection limit 29 4325
. Missing 565 4890

URXAAM - N-ace-S-(2-carbamoylethyl)-L-cys(ng/mL)

Variable Name:
URXAAM
SAS Label:
N-ace-S-(2-carbamoylethyl)-L-cys(ng/mL)
English Text:
N-acetyl-S-(2-carbamoylethyl)-L-cysteine(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.56 to 5350 Range of Values 4325 4325
. Missing 565 4890

URDAAMLC - N-ace-S-(2-carbamoylethyl)-L-cys comt

Variable Name:
URDAAMLC
SAS Label:
N-ace-S-(2-carbamoylethyl)-L-cys comt
English Text:
N-acetyl-S-(2-carbamoylethyl)-L-cysteine comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 4322 4322
1 Below lower detection limit 3 4325
. Missing 565 4890

URXAMC - N-ace-S-(N-methlcarbamoyl)-L-cys(ng/mL)

Variable Name:
URXAMC
SAS Label:
N-ace-S-(N-methlcarbamoyl)-L-cys(ng/mL)
English Text:
N-acetyl-S-(N-methylcarbamoyl)-L-cysteine(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
4.43 to 46300 Range of Values 4325 4325
. Missing 565 4890

URDAMCLC - N-ace-S-(N-methlcarbamoyl)-L-cys comt

Variable Name:
URDAMCLC
SAS Label:
N-ace-S-(N-methlcarbamoyl)-L-cys comt
English Text:
N-acetyl-S-(N-methylcarbamoyl)-L-cysteine comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 4297 4297
1 Below lower detection limit 28 4325
. Missing 565 4890

URXATC - 2-amnothiazolne-4-carbxylic acid(ng/mL)

Variable Name:
URXATC
SAS Label:
2-amnothiazolne-4-carbxylic acid(ng/mL)
English Text:
2-aminothiazoline-4-carboxylic acid(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
20.9 to 3250 Range of Values 4325 4325
. Missing 565 4890

URDATCLC - 2-amnothiazolne-4-carbxylic acid comt

Variable Name:
URDATCLC
SAS Label:
2-amnothiazolne-4-carbxylic acid comt
English Text:
2-amnothiazolne-4-carbxylic acid comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 3904 3904
1 Below lower detection limit 421 4325
. Missing 565 4890

URXBMA - N-acetyl-S-(benzyl)-L-cysteine(ng/mL)

Variable Name:
URXBMA
SAS Label:
N-acetyl-S-(benzyl)-L-cysteine(ng/mL)
English Text:
N-acetyl-S-(benzyl)-L-cysteine(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.354 to 1630 Range of Values 4325 4325
. Missing 565 4890

URDBMALC - N-acetyl-S-(benzyl)-L-cysteine comt

Variable Name:
URDBMALC
SAS Label:
N-acetyl-S-(benzyl)-L-cysteine comt
English Text:
N-acetyl-S-(benzyl)-L-cysteine comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 4313 4313
1 Below lower detection limit 12 4325
. Missing 565 4890

URXBPM - N-acetyl-S-(n-propyl)-L-cysteine(ng/mL)

Variable Name:
URXBPM
SAS Label:
N-acetyl-S-(n-propyl)-L-cysteine(ng/mL)
English Text:
N-acetyl-S-(n-propyl)-L-cysteine(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.85 to 1490 Range of Values 4325 4325
. Missing 565 4890

URDBPMLC - N-acetyl-S-(n-propyl)-L-cysteine comt

Variable Name:
URDBPMLC
SAS Label:
N-acetyl-S-(n-propyl)-L-cysteine comt
English Text:
N-acetyl-S-(n-propyl)-L-cysteine comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 3197 3197
1 Below lower detection limit 1128 4325
. Missing 565 4890

URXCEM - N-acetyl-S-(2-carbxyethyl)-L-cys(ng/mL)

Variable Name:
URXCEM
SAS Label:
N-acetyl-S-(2-carbxyethyl)-L-cys(ng/mL)
English Text:
N-acetyl-S-(2-carboxyethyl)-L-cysteine(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
4.92 to 3030 Range of Values 4325 4325
. Missing 565 4890

URDCEMLC - N-acetyl-S-(2-carbxyethyl)-L-cys comt

Variable Name:
URDCEMLC
SAS Label:
N-acetyl-S-(2-carbxyethyl)-L-cys comt
English Text:
N-acetyl-S- (2-carboxyethyl)-L-cysteine comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 4268 4268
1 Below lower detection limit 57 4325
. Missing 565 4890

URXCYHA - CYHA cysteine (ng/mL)

Variable Name:
URXCYHA
SAS Label:
CYHA cysteine (ng/mL)
English Text:
N-Acetyl-S-(1-cyano-2-hydroxyethyl)-L-cysteine (CYHA) (ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.84 to 414 Range of Values 4325 4325
. Missing 565 4890

URDCYALC - CYHA cysteine comment code

Variable Name:
URDCYALC
SAS Label:
CYHA cysteine comment code
English Text:
N-Acetyl-S-(1-cyano-2-hydroxyethyl)-L-cysteine (CYHA) comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 673 673
1 Below lower detection limit 3652 4325
. Missing 565 4890

URXCYM - N-acetyl-S-(2-cyanoethyl)-L-cyst(ng/mL)

Variable Name:
URXCYM
SAS Label:
N-acetyl-S-(2-cyanoethyl)-L-cyst(ng/mL)
English Text:
N-acetyl-S-(2-cyanoethyl)-L-cysteine(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.354 to 2800 Range of Values 4325 4325
. Missing 565 4890

URDCYMLC - N-acetyl-S-(2-cyanoethyl)-L-cyst comt

Variable Name:
URDCYMLC
SAS Label:
N-acetyl-S-(2-cyanoethyl)-L-cyst comt
English Text:
N-acetyl-S-(2-cyanoethyl)-L-cysteine comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 3501 3501
1 Below lower detection limit 824 4325
. Missing 565 4890

URXDHB - N-ace-S-(3,4-dihidxybutl)-L-cys(ng/mL)

Variable Name:
URXDHB
SAS Label:
N-ace-S-(3,4-dihidxybutl)-L-cys(ng/mL)
English Text:
N-acetyl-S-(3,4-dihidroxybutyl)-L-cysteine(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
16 to 3890 Range of Values 4325 4325
. Missing 565 4890

URDDHBLC - N-ace-S-(3,4-dihidxybutl)-L-cys comt

Variable Name:
URDDHBLC
SAS Label:
N-ace-S-(3,4-dihidxybutl)-L-cys comt
English Text:
N-acetyl-S-(3,4-dihidroxybutyl)-L-cysteine comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 4325 4325
1 Below lower detection limit 0 4325
. Missing 565 4890

URXGAM - N-ac-S-(2-carbmo-2-hydxel)-L-cys(ng/mL)

Variable Name:
URXGAM
SAS Label:
N-ac-S-(2-carbmo-2-hydxel)-L-cys(ng/mL)
English Text:
N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
6.65 to 383 Range of Values 4325 4325
. Missing 565 4890

URDGAMLC - N-ac-S-(2-carbmo-2-hydxel)-L-cys comt

Variable Name:
URDGAMLC
SAS Label:
N-ac-S-(2-carbmo-2-hydxel)-L-cys comt
English Text:
N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1792 1792
1 Below lower detection limit 2533 4325
. Missing 565 4890

URXHEM - N-ace-S-(2-hydroxyethyl)-L-cys(ng/mL)

Variable Name:
URXHEM
SAS Label:
N-ace-S-(2-hydroxyethyl)-L-cys(ng/mL)
English Text:
N-acetyl-S-(2-hydroxyethyl)-L-cysteine(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.559 to 71.3 Range of Values 4325 4325
. Missing 565 4890

URDHEMLC - N-ace-S-(2-hydroxyethyl)-L-cys comt

Variable Name:
URDHEMLC
SAS Label:
N-ace-S-(2-hydroxyethyl)-L-cys comt
English Text:
N-acetyl-S-(2-hydroxyethyl)-L-cysteine comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2016 2016
1 Below lower detection limit 2309 4325
. Missing 565 4890

URXHP2 - N-ace-S-(2-hydroxypropyl)-L-cys(ng/mL)

Variable Name:
URXHP2
SAS Label:
N-ace-S-(2-hydroxypropyl)-L-cys(ng/mL)
English Text:
N-acetyl-S- (2-hydroxypropyl)-L-cysteine(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3.75 to 10100 Range of Values 4325 4325
. Missing 565 4890

URDHP2LC - N-ace-S-(2-hydroxypropyl)-L-cys comt

Variable Name:
URDHP2LC
SAS Label:
N-ace-S-(2-hydroxypropyl)-L-cys comt
English Text:
N-acetyl-S- (2-hydroxypropyl)-L-cysteine comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 4097 4097
1 Below lower detection limit 228 4325
. Missing 565 4890

URXHPM - N-ace-S-(3-hydroxypropyl)-L-cys(ng/mL)

Variable Name:
URXHPM
SAS Label:
N-ace-S-(3-hydroxypropyl)-L-cys(ng/mL)
English Text:
N-acetyl-S- (3-hydroxypropyl)-L-cysteine(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
9.2 to 14600 Range of Values 4325 4325
. Missing 565 4890

URDHPMLC - N-ace-S-(3-hydroxypropyl)-L-cys comt

Variable Name:
URDHPMLC
SAS Label:
N-ace-S-(3-hydroxypropyl)-L-cys comt
English Text:
N-acetyl-S- (3-hydroxypropyl)-L-cysteine comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 4312 4312
1 Below lower detection limit 13 4325
. Missing 565 4890

URXIPM3 - IPM3 cysteine (ng/mL)

Variable Name:
URXIPM3
SAS Label:
IPM3 cysteine (ng/mL)
English Text:
N-Acetyl-S-(4-hydroxy-2-methyl-2-buten-1-yl)-L-cysteine (ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.85 to 912 Range of Values 4324 4324
. Missing 566 4890

URDPM3LC - IPM3 cysteine comment code

Variable Name:
URDPM3LC
SAS Label:
IPM3 cysteine comment code
English Text:
N-Acetyl-S-(4-hydroxy-2-methyl-2-buten-1-yl)-L-cysteine comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 3566 3566
1 Below lower detection limit 758 4324
. Missing 566 4890

URXMAD - Mandelic acid(ng/mL)

Variable Name:
URXMAD
SAS Label:
Mandelic acid(ng/mL)
English Text:
Mandelic acid(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
8.5 to 12700 Range of Values 4325 4325
. Missing 565 4890

URDMADLC - Mandelic acid comment code

Variable Name:
URDMADLC
SAS Label:
Mandelic acid comment code
English Text:
Mandelic acid comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 4278 4278
1 Below lower detection limit 47 4325
. Missing 565 4890

URXMB3 - N-A-S-(4-hydrxy-2-butenyl)-L-cys(ng/mL)

Variable Name:
URXMB3
SAS Label:
N-A-S-(4-hydrxy-2-butenyl)-L-cys(ng/mL)
English Text:
N-acetyl-S- (4-hydroxy-2-butenyl)-L-cysteine (ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.424 to 444 Range of Values 4325 4325
. Missing 565 4890

URDMB3LC - N-A-S-(4-hydrxy-2-butenyl)-L-cys comt

Variable Name:
URDMB3LC
SAS Label:
N-A-S-(4-hydrxy-2-butenyl)-L-cys comt
English Text:
N-acetyl-S- (4-hydroxy-2-butenyl)-L-cysteine comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 4215 4215
1 Below lower detection limit 110 4325
. Missing 565 4890

URXPHG - Phenylglyoxylic acid(ng/mL)

Variable Name:
URXPHG
SAS Label:
Phenylglyoxylic acid(ng/mL)
English Text:
Phenylglyoxylic acid(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
8.5 to 7940 Range of Values 4325 4325
. Missing 565 4890

URDPHGLC - Phenylglyoxylic acid comment code

Variable Name:
URDPHGLC
SAS Label:
Phenylglyoxylic acid comment code
English Text:
Phenylglyoxylic acid comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 4319 4319
1 Below lower detection limit 6 4325
. Missing 565 4890

URXPMM - N-A-S-(3-hydrxprpl-1-metl)-L-cys(ng/mL)

Variable Name:
URXPMM
SAS Label:
N-A-S-(3-hydrxprpl-1-metl)-L-cys(ng/mL)
English Text:
N-acetyl-S-(3-hydroxypropyl-1-methyl)-L-cysteine(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
9.39 to 12600 Range of Values 4325 4325
. Missing 565 4890

URDPMMLC - N-A-S-(3-hydrxprpl-1-metl)-L-cys comt

Variable Name:
URDPMMLC
SAS Label:
N-A-S-(3-hydrxprpl-1-metl)-L-cys comt
English Text:
N-acetyl-S-(3-hydroxypropyl-1-methyl)-L-cysteine comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 4325 4325
1 Below lower detection limit 0 4325
. Missing 565 4890

URXTTC - 2-Thioxothiazolidine-4-carboxylic acid

Variable Name:
URXTTC
SAS Label:
2-Thioxothiazolidine-4-carboxylic acid
English Text:
2-Thioxothiazolidine-4-carboxylic acid
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7.9 to 1760 Range of Values 4325 4325
. Missing 565 4890

URDTTCLC - 2-Thoxothazlidne-4-carbxylic comt

Variable Name:
URDTTCLC
SAS Label:
2-Thoxothazlidne-4-carbxylic comt
English Text:
2-Thioxothiazolidine-4-carboxylic acid comment code
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1523 1523
1 Below lower detection limit 2802 4325
. Missing 565 4890