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 toxics 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

Examined participants aged 18 years and older from a one-third sample were eligible. Additionally, to oversample adult smokers, those participants aged 18 years and older, not in the regular one-third subsample, who smoked at least 100 cigarettes in their entire lifetime (SMQ020=1) and now smoke cigarettes every day (SMQ040=1), were also included in this special subsample.

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.

There were no changes to the lab method, lab equipment, or lab site for this component in the NHANES 2013-2014 cycle.

Laboratory Method Files

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 second examinations on previously examined participants and blind split samples collected on “dry run” sessions.

NCHS developed and distributed a quality control protocol for all CDC and contract laboratories, which outlined the Westgard rules (Westgard, et al. 1981) used 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 CDC/NCEH Tobacco and Volatile Branch 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 2013-2014 Laboratory Data Overview for general information on NHANES laboratory data.

Subsample Weights

VOC metabolites in urine were assessed in a special smoking subsample of participants aged 18 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 with the key survey design and basic demographic variables. The NHANES 2013-2014 Demographics File contains demographic and 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 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.

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

VARIABLE Analyte LLOD
URXAAM Urinary N-Acetyl-S-(2-carbamoylethyl)-L-cysteine 2.20
URXAMC Urinary N-Acetyl-S-(N-methylcarbamoyl)-L-cysteine 6.26
URXATC Urinary 2-Aminothiazoline-4-carboxylic acid 15.0
URXBMA Urinary N-Acetyl-S-(benzyl)-L-cysteine 0.500
URXBPM Urinary N-Acetyl-S-(n-propyl)-L-cysteine 1.20
URXCEM Urinary N-Acetyl-S-(2-carboxyethyl)-L-cysteine 6.96
URXCYM Urinary N-Acetyl-S-(2-cyanoethyl)-L-cysteine 0.500
URX1DC Urinary N-Acetyl-S-(1,2-dichlorovinyl)-L-cysteine 12.6
URX2DC Urinary N-Acetyl-S-(2,2-dichlorovinyl)-L-cysteine 4.70
URXDHB Urinary N-Acetyl-S-(3,4-dihydroxybutyl)-L-cysteine 5.25
URXDPM Urinary N-Acetyl-S-(dimethylphenyl)-L-cysteine 0.500
URXGAM Urinary N-Acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine 9.40
URXHEM Urinary N-Acetyl-S-(2-hydroxyethyl)-L-cysteine 0.791
URXHPM Urinary N-Acetyl-S-(3-hydroxypropyl)-L-cysteine 13.0
URXHP2 Urinary N-Acetyl-S-(2-hydroxypropyl)-L-cysteine 5.30
URXPMM Urinary N-Acetyl-S-(3-hydroxypropyl-1-methyl)-L-cysteine 3.00
URXMAD Urinary Mandelic acid 12.0
URX2MH Urinary 2-Methylhippuric acid 5.00
URX34M Urinary 3- and 4-Methylhippuric acid 8.00
URXMB1 Urinary N-Acetyl-S-(1-hydroxymethyl-2-propenyl)-L-cysteine 0.700
URXMB2 Urinary N-Acetyl-S-(2-hydroxy-3-butenyl)-L-cysteine 0.700
URXMB3 Urinary N-Acetyl-S-(4-hydroxy-2-butenyl)-L-cysteine 0.600
URXPHE Urinary N-Acetyl-S-(phenyl-2-hydroxyethyl)-L-cysteine 0.700
URXPHG Urinary Phenylglyoxylic acid 12.0
URXPMA Urinary N-Acetyl-S-(phenyl)-L-cysteine 0.600
URXTCV Urinary N-Acetyl-S-(trichlorovinyl)-L-cysteine 3.00
URXTTC Urinary 2-Thioxothiazolidine-4-carboxylic acid 11.2

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.

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 18 YEARS - 150 YEARS

WTFSM - Two Year Smoking Weights

Variable Name:
WTFSM
SAS Label:
Two Year Smoking Weights
English Text:
Two Year Smoking Weights
Target:
Both males and females 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
6426.907677 to 456840.9815 Range of Values 2546 2546
0 No Lab Result 59 2605
. Missing 0 2605

URXUCR - Creatinine, urine (mg/dL)

Variable Name:
URXUCR
SAS Label:
Creatinine, urine (mg/dL)
English Text:
Creatinine, urine (mg/dL)
Target:
Both males and females 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5 to 546 Range of Values 2544 2544
. Missing 61 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
8.9 to 13.6 Range of Values 2347 2347
. Missing 258 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1 1
1 Below lower detection limit 2346 2347
. Missing 258 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3.32 to 8.97 Range of Values 2420 2420
. Missing 185 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1 1
1 Below lower detection limit 2419 2420
. Missing 185 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3.54 to 2220 Range of Values 2266 2266
. Missing 339 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2112 2112
1 Below lower detection limit 154 2266
. Missing 339 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5.66 to 14400 Range of Values 2492 2492
. Missing 113 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2477 2477
1 Below lower detection limit 15 2492
. Missing 113 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.56 to 2750 Range of Values 2366 2366
. Missing 239 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2363 2363
1 Below lower detection limit 3 2366
. Missing 239 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
4.43 to 4820 Range of Values 2490 2490
. Missing 115 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2486 2486
1 Below lower detection limit 4 2490
. Missing 115 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
10.6 to 2030 Range of Values 2370 2370
. Missing 235 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2241 2241
1 Below lower detection limit 129 2370
. Missing 235 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.354 to 539 Range of Values 2489 2489
. Missing 116 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2463 2463
1 Below lower detection limit 26 2489
. Missing 116 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.85 to 618 Range of Values 2492 2492
. Missing 113 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1735 1735
1 Below lower detection limit 757 2492
. Missing 113 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
4.92 to 6480 Range of Values 2479 2479
. Missing 126 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2455 2455
1 Below lower detection limit 24 2479
. Missing 126 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.354 to 2860 Range of Values 2428 2428
. Missing 177 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2238 2238
1 Below lower detection limit 190 2428
. Missing 177 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3.71 to 3280 Range of Values 2502 2502
. Missing 103 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2501 2501
1 Below lower detection limit 1 2502
. Missing 103 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.354 to 1.93 Range of Values 2340 2340
. Missing 265 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 9 9
1 Below lower detection limit 2331 2340
. Missing 265 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
6.65 to 297 Range of Values 2501 2501
. Missing 104 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1202 1202
1 Below lower detection limit 1299 2501
. Missing 104 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.559 to 47.6 Range of Values 2452 2452
. Missing 153 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1304 1304
1 Below lower detection limit 1148 2452
. Missing 153 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3.75 to 4100 Range of Values 2467 2467
. Missing 138 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2339 2339
1 Below lower detection limit 128 2467
. Missing 138 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
9.2 to 27400 Range of Values 2475 2475
. Missing 130 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2470 2470
1 Below lower detection limit 5 2475
. Missing 130 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
8.5 to 9090 Range of Values 2422 2422
. Missing 183 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2381 2381
1 Below lower detection limit 41 2422
. Missing 183 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.495 to 1.56 Range of Values 2448 2448
. Missing 157 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 45 45
1 Below lower detection limit 2403 2448
. Missing 157 2605

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

Variable Name:
URXMB2
SAS Label:
N-Ac-S-(2-hydrxy-3-butnyl)-L-cys(ng/mL)
English Text:
N-acetyl-S- (2-hydroxy-3-butenyl)-L-cysteine (ng/mL)
Target:
Both males and females 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.495 to 30.6 Range of Values 2486 2486
. Missing 119 2605

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

Variable Name:
URDMB2LC
SAS Label:
N-Ac-S-(2-hydrxy-3-butnyl)-L-cys comt
English Text:
N-acetyl-S- (2-hydroxy-3-butenyl)-L-cysteine comment code
Target:
Both males and females 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 623 623
1 Below lower detection limit 1863 2486
. Missing 119 2605

URXMB3 - N-A-S-(4-hydrxy-2butn-l-yl)-L-cys(ng/mL)

Variable Name:
URXMB3
SAS Label:
N-A-S-(4-hydrxy-2butn-l-yl)-L-cys(ng/mL)
English Text:
N-acetyl-S- (4-hydroxy-2-butenyl)-L-cysteine (ng/mL)
Target:
Both males and females 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.424 to 361 Range of Values 2395 2395
. Missing 210 2605

URDMB3LC - N-A-S-(4-hydrxy-2butn-l-yl)-L-cys comt

Variable Name:
URDMB3LC
SAS Label:
N-A-S-(4-hydrxy-2butn-l-yl)-L-cys comt
English Text:
N-acetyl-S- (4-hydroxy-2-butenyl)-L-cysteine comment code
Target:
Both males and females 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2370 2370
1 Below lower detection limit 25 2395
. Missing 210 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.495 to 138 Range of Values 2441 2441
. Missing 164 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1081 1081
1 Below lower detection limit 1360 2441
. Missing 164 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
8.5 to 13000 Range of Values 2435 2435
. Missing 170 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2412 2412
1 Below lower detection limit 23 2435
. Missing 170 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.424 to 28.3 Range of Values 2434 2434
. Missing 171 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 909 909
1 Below lower detection limit 1525 2434
. Missing 171 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2.12 to 20800 Range of Values 2418 2418
. Missing 187 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2417 2417
1 Below lower detection limit 1 2418
. Missing 187 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2.12 2.12 2486 2486
. Missing 119 2605

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 18 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 2486 2486
. Missing 119 2605

URXTTC - 2-thoxothazlidne-4-carbxylic acid(ng/mL)

Variable Name:
URXTTC
SAS Label:
2-thoxothazlidne-4-carbxylic acid(ng/mL)
English Text:
2-thioxothiazolidine-4-carboxylic acid(ng/mL)
Target:
Both males and females 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7.9 to 1130 Range of Values 2504 2504
. Missing 101 2605

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 18 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 948 948
1 Below lower detection limit 1556 2504
. Missing 101 2605