Table of Contents

Component Description

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 were eligible, and participants aged 6 years and older from a one-third subsample 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.

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

Laboratory Method Files

Urinary VOC Metabolites Laboratory Procedure Manual (November 2018)

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 NHANES Laboratory Procedures Manual (LPM). Vials are stored under appropriate frozen (–20°C) conditions until they are shipped to National Center for Environmental Health for testing.

The NHANES QA/QC protocols meet the 1988 Clinical Laboratory Improvement Act 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 quality-control 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 quality control 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’ quality control and quality assurance 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

Refer to the 2015-2016 Laboratory Data Overview for general information on NHANES laboratory data.

Subsample Weights

VOC metabolites in urine were measured in a one-third subsample of participants aged 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 2015-2016 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

SAS LABEL

  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)

15.0

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

URX1DC

N-Acetyl-S-(1,2-dichlorovinyl)-L-cysteine (ng/mL)

12.6

URX2DC

N-Acetyl-S-(2,2-dichlorovinyl)-L-cysteine (ng/mL)

13.9

URXDHB

N-Acetyl-S-(3,4-dihydroxybutyl)-L-cysteine (ng/mL)

5.25

URXDPM

N-Acetyl-S-(dimethylphenyl)-L-cysteine (ng/mL)

0.500

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)

5.30

URXIPM1

N-Acetyl-S-(2-hydroxy-3-methyl-3-butenyl)-L-cysteine +

N-Acetyl-S-(2-hydroxy-2-methyl-3-butenyl)-L-cysteine

1.43

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

URXMB1

N-Acetyl-S-(1-hydroxymethyl-2-propenyl)-L-cysteine (ng/mL)

0.700

URXMB2

N-Acetyl-S-(2-hydroxy-3-butenyl)-L-cysteine (ng/mL)

0.700

URXMB3

N-Acetyl-S-(4-hydroxy-2-butenyl)-L-cysteine (ng/mL)

0.600

URXPHE

N-Acetyl-S-(phenyl-2-hydroxyethyl)-L-cysteine (ng/mL)

0.700

URXPHG

Phenylglyoxylic acid (ng/mL)

12.0

URXPMA

N-Acetyl-S-(phenyl)-L-cysteine (ng/mL)

0.600

URXPMM

N-Acetyl-S-(3-hydroxypropyl-1-methyl)-L-cysteine (ng/mL)

3.00

URXTCV

N-Acetyl-S-(trichlorovinyl)-L-cysteine (ng/mL)

3.00

Please refer to the NHANES Analytic Guidelines and the on-line NHANES Tutorial further details on the use of sample weights and other analytic issues.

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

WTSA2YR - Subsample A Weights

Variable Name:
WTSA2YR
SAS Label:
Subsample A Weights
English Text:
Subsample A Weights
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
6552.119284 to 708844.24678 Range of Values 3231 3231
0 Participants 6+ years with no lab specimen 48 3279
. Missing 0 3279

URX1DC - N-acel-S-(1,2-dichlorovinl)-L-cys(ng/mL)

Variable Name:
URX1DC
SAS Label:
N-acel-S-(1,2-dichlorovinl)-L-cys(ng/mL)
English Text:
N-acetyl-S-(1,2-dichlorovinyl)-L-cysteine (ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
8.9 8.9 2886 2886
. Missing 393 3279

URD1DCLC - N-acel-S-(1,2-dichlorovinl)-L-cys comt

Variable Name:
URD1DCLC
SAS Label:
N-acel-S-(1,2-dichlorovinl)-L-cys comt
English Text:
N-acetyl-S-(1,2-dichlorovinyl)-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 0 0
1 Below lower detection limit 2886 2886
. Missing 393 3279

URX2DC - N-acel-S-(2,2-dichlorvinyl)-L-cys(ng/mL)

Variable Name:
URX2DC
SAS Label:
N-acel-S-(2,2-dichlorvinyl)-L-cys(ng/mL)
English Text:
N-acetyl-S-(2,2-dichlorovinyl)-L-cysteine (ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
9.8 9.8 2831 2831
. Missing 448 3279

URD2DCLC - N-acel-S-(2,2-dichlorvinyl)-L-cys comt

Variable Name:
URD2DCLC
SAS Label:
N-acel-S-(2,2-dichlorvinyl)-L-cys comt
English Text:
N-acetyl-S-(2,2-dichlorovinyl)-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 0 0
1 Below lower detection limit 2831 2831
. Missing 448 3279

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 2330 Range of Values 3015 3015
. Missing 264 3279

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 2727 2727
1 Below lower detection limit 288 3015
. Missing 264 3279

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 30700 Range of Values 3014 3014
. Missing 265 3279

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 3001 3001
1 Below lower detection limit 13 3014
. Missing 265 3279

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 1640 Range of Values 3015 3015
. Missing 264 3279

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 3012 3012
1 Below lower detection limit 3 3015
. Missing 264 3279

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 3350 Range of Values 2965 2965
. Missing 314 3279

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 2949 2949
1 Below lower detection limit 16 2965
. Missing 314 3279

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
10.6 to 2390 Range of Values 3015 3015
. Missing 264 3279

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 2938 2938
1 Below lower detection limit 77 3015
. Missing 264 3279

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 1330 Range of Values 3014 3014
. Missing 265 3279

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 3003 3003
1 Below lower detection limit 11 3014
. Missing 265 3279

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 707 Range of Values 2952 2952
. Missing 327 3279

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 2220 2220
1 Below lower detection limit 732 2952
. Missing 327 3279

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 3570 Range of Values 3015 3015
. Missing 264 3279

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 3003 3003
1 Below lower detection limit 12 3015
. Missing 264 3279

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 452 Range of Values 3015 3015
. Missing 264 3279

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 440 440
1 Below lower detection limit 2575 3015
. Missing 264 3279

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 1480 Range of Values 3015 3015
. Missing 264 3279

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 2369 2369
1 Below lower detection limit 646 3015
. Missing 264 3279

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
16.1 to 3140 Range of Values 2691 2691
. Missing 588 3279

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 2691 2691
1 Below lower detection limit 0 2691
. Missing 588 3279

URXDPM - N-ace-S-(dimethylphenyl)-L-cys(ng/mL)

Variable Name:
URXDPM
SAS Label:
N-ace-S-(dimethylphenyl)-L-cys(ng/mL)
English Text:
N-acetyl-S-(dimethylphenyl)-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 6.38 Range of Values 3015 3015
. Missing 264 3279

URDDPMLC - N-ace-S-(dimethylphenyl)-L-cys comt

Variable Name:
URDDPMLC
SAS Label:
N-ace-S-(dimethylphenyl)-L-cys comt
English Text:
N-acetyl-S-(dimethylphenyl)-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 5 5
1 Below lower detection limit 3010 3015
. Missing 264 3279

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 114 Range of Values 3015 3015
. Missing 264 3279

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 1197 1197
1 Below lower detection limit 1818 3015
. Missing 264 3279

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 49.4 Range of Values 3015 3015
. Missing 264 3279

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 1546 1546
1 Below lower detection limit 1469 3015
. Missing 264 3279

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 9830 Range of Values 3014 3014
. Missing 265 3279

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 2862 2862
1 Below lower detection limit 152 3014
. Missing 265 3279

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 11900 Range of Values 2821 2821
. Missing 458 3279

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 2816 2816
1 Below lower detection limit 5 2821
. Missing 458 3279

URXIPM1 - IPM1 cysteine (ng/mL)

Variable Name:
URXIPM1
SAS Label:
IPM1 cysteine (ng/mL)
English Text:
N-Acetyl-S-(2-hydroxy-3-methyl-3-butenyl)-L-cysteine + N-Acetyl-S-(2-hydroxy-2-methyl-3-butenyl)-L-cysteine (ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.01 to 80.3 Range of Values 3015 3015
. Missing 264 3279

URDPM1LC - IPM1 cysteine comment code

Variable Name:
URDPM1LC
SAS Label:
IPM1 cysteine comment code
English Text:
N-Acetyl-S-(2-hydroxy-3-methyl-3-butenyl)-L-cysteine + N-Acetyl-S-(2-hydroxy-2-methyl-3-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 2225 2225
1 Below lower detection limit 790 3015
. Missing 264 3279

URXIPM3 - IPM3 cysteine (ng/mL)

Variable Name:
URXIPM3
SAS Label:
IPM3 cysteine (ng/mL)
English Text:
N-Acetyl-S-(4-hydroxy-2-methyl-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
0.85 to 492 Range of Values 3015 3015
. Missing 264 3279

URDPM3LC - IPM3 cysteine comment code

Variable Name:
URDPM3LC
SAS Label:
IPM3 cysteine comment code
English Text:
N-Acetyl-S-(4-hydroxy-2-methyl-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 2419 2419
1 Below lower detection limit 596 3015
. Missing 264 3279

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 4330 Range of Values 3008 3008
. Missing 271 3279

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 2971 2971
1 Below lower detection limit 37 3008
. Missing 271 3279

URXMB1 - N-A-S-(1-hydrxmet)-2-Prpn)-L-cys(ng/mL)

Variable Name:
URXMB1
SAS Label:
N-A-S-(1-hydrxmet)-2-Prpn)-L-cys(ng/mL)
English Text:
N-acetyl-S-(1-hydroxymethyl)-2-propenyl)-L-cysteine(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.495 to 1.54 Range of Values 2987 2987
. Missing 292 3279

URDMB1LC - N-A-S-(1-hydrxmet)-2-Prpn)-L-cys comt

Variable Name:
URDMB1LC
SAS Label:
N-A-S-(1-hydrxmet)-2-Prpn)-L-cys comt
English Text:
N-acetyl-S-(1-hydroxymethyl)-2-Propenyl)-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 14 14
1 Below lower detection limit 2973 2987
. Missing 292 3279

URXMB2 - N-Ac-S-(2-hydrxy-3-butenyl)-L-cys(ng/mL)

Variable Name:
URXMB2
SAS Label:
N-Ac-S-(2-hydrxy-3-butenyl)-L-cys(ng/mL)
English Text:
N-acetyl-S-(2-hydroxy-3-butenyl)-L-cysteine (ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.495 to 94.9 Range of Values 3015 3015
. Missing 264 3279

URDMB2LC - N-Ac-S-(2-hydrxy-3-butenyl)-L-cys comt

Variable Name:
URDMB2LC
SAS Label:
N-Ac-S-(2-hydrxy-3-butenyl)-L-cys comt
English Text:
N-acetyl-S-(2-hydroxy-3-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 279 279
1 Below lower detection limit 2736 3015
. Missing 264 3279

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 407 Range of Values 3015 3015
. Missing 264 3279

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 2843 2843
1 Below lower detection limit 172 3015
. Missing 264 3279

URXPHE - N-ace-S-(phenl-2-hydxyetl)-L-cys(ng/mL)

Variable Name:
URXPHE
SAS Label:
N-ace-S-(phenl-2-hydxyetl)-L-cys(ng/mL)
English Text:
N-acetyl-S-(phenyl-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
0.495 to 48.6 Range of Values 2947 2947
. Missing 332 3279

URDPHELC - N-ace-S-(phenl-2-hydxyetl)-L-cys comt

Variable Name:
URDPHELC
SAS Label:
N-ace-S-(phenl-2-hydxyetl)-L-cys comt
English Text:
N-acetyl-S-(phenyl-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 1480 1480
1 Below lower detection limit 1467 2947
. Missing 332 3279

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 5320 Range of Values 3013 3013
. Missing 266 3279

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 2991 2991
1 Below lower detection limit 22 3013
. Missing 266 3279

URXPMA - N-acetyl-S-(phenyl)-L-cysteine(ng/mL)

Variable Name:
URXPMA
SAS Label:
N-acetyl-S-(phenyl)-L-cysteine(ng/mL)
English Text:
N-acetyl-S-(phenyl)-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 28 Range of Values 3015 3015
. Missing 264 3279

URDPMALC - N-acetyl-S-(phenyl)-L-cysteine comt

Variable Name:
URDPMALC
SAS Label:
N-acetyl-S-(phenyl)-L-cysteine comt
English Text:
N-acetyl-S-(phenyl)-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 1426 1426
1 Below lower detection limit 1589 3015
. Missing 264 3279

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
14.1 to 25100 Range of Values 3015 3015
. Missing 264 3279

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 3015 3015
1 Below lower detection limit 0 3015
. Missing 264 3279

URXTCV - N-acetyl-S-(trichlorovinyl)-L-cys(ng/mL)

Variable Name:
URXTCV
SAS Label:
N-acetyl-S-(trichlorovinyl)-L-cys(ng/mL)
English Text:
N-acetyl-S-(trichlorovinyl)-L-cysteine(ng/mL)
Target:
Both males and females 3 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2.12 2.12 3015 3015
. Missing 264 3279

URDTCVLC - N-acetyl-S-(trichlorovinyl)-L-cys comt

Variable Name:
URDTCVLC
SAS Label:
N-acetyl-S-(trichlorovinyl)-L-cys comt
English Text:
N-acetyl-S-(trichlorovinyl)-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 0 0
1 Below lower detection limit 3015 3015
. Missing 264 3279