Table of Contents

Locator Record

Title: Urine Flow Rate (UCFLOW_F )
Contact Number: 1-866-441-NCHS
Years of Content: 2009 - 2010
First Published: September, 2011
Revised: NA
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject:Urine Flow Rate
Record Source: NHANES 2009 - 2010
Survey Methodology: NHANES 2009 - 2010 is a stratified multistage probability sample of the civilian non-institutionalized population of the U.S.
Medium: NHANES Web site; SAS transport files

Component Description

The Urine Flow Rate (or urine excretion rate) is a measurement of the quantity of urine produced in a specified period of time. Urine analyte concentrations from single determinations (spot urines) can vary depending on the water content of the urine. Due to this variation, the urine flow rate is a more accurate calculation used to determine urine analyte concentrations, especially exposure to environmental chemicals. When used to determine urine analyte concentrations, the urine excretion rate (mg/min) is the product of the urine flow rate (mL/min) and the urine analyte concentration (mg/mL).

Eligible Sample

Participants aged 6 years and older were tested.

Description of Laboratory Methodology

Participants will be asked to record their time of last void before coming to the MEC. Participants will then be asked to void at the MEC where the time of collection and volume of the urine will be recorded. The volume of the urine sample collected at the MEC will be measured and the urine flow rate will be calculated from this information. The urine flow rate is calculated by dividing the total volume of the urine sample collected in the MEC, by the total time between the previous urine sample collection and the urine sample collected in the MEC. There may be a maximum of 3 urine flow rates for a participant which depends on the total number of spot urines which are collected in the MEC.

Detailed instructions on specimen collection and processing can be found in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM).

Data Processing and Editing

Read the General Documentation on Laboratory Data file for detailed data processing and editing protocols. The analytical methods are described in the Description of Laboratory Methodology section above.

Laboratory Quality Assurance and Monitoring

The NHANES quality control and quality assurance protocols (QA/QC) meet the 1988 Clinical Laboratory Improvement Act mandates. Detailed QA/QC instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM) . Read the General Documentation on Laboratory Data file for detailed QA/QC protocols.

Analytic Notes

NHANES Survey Design:

The analysis of NHANES laboratory data must be conducted with the key survey design and basic demographic variables. The Demographic file contains: Status Variables providing core information on the survey participant including examination status, Recoded Demographic Variables including age, gender, race etc., and Interview and Examination Sample Weight Variables and Survey Design Variables. The Questionnaire Data Files contain socio-economic data, health indicators, and other related information collected during household interviews. The Phlebotomy Examination file includes auxiliary information on duration of fasting, the time of day of the venipuncture, and the conditions precluding venipuncture. The Demographic, Questionnaire and Phlebotomy Examination files may be linked to the laboratory data file using the unique survey participant identifier SEQN.

Exam sample weights should be used for analyses.

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.

The variable named URX___ provides the analytic result for the analyte.

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 6 YEARS - 150 YEARS

URXVOL1 - The volume of urine collection #1

Variable Name:
URXVOL1
SAS Label:
The volume of urine collection #1
English Text:
The volume of urine collection #1
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 524 Range of Values 8433 8433
. Missing 158 8591

URDFLOW1 - Urine #1 Flow Rate

Variable Name:
URDFLOW1
SAS Label:
Urine #1 Flow Rate
English Text:
Urine #1 Flow Rate
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 39.8 Range of Values 7727 7727
. Missing 864 8591

URXVOL2 - The volume of urine collection #2

Variable Name:
URXVOL2
SAS Label:
The volume of urine collection #2
English Text:
The volume of urine collection #2
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 420 Range of Values 1315 1315
. Missing 7276 8591

URDFLOW2 - Urine #2 Flow Rate

Variable Name:
URDFLOW2
SAS Label:
Urine #2 Flow Rate
English Text:
Urine #2 Flow Rate
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 13.692 Range of Values 1305 1305
. Missing 7286 8591

URXVOL3 - The volume of urine collection #3

Variable Name:
URXVOL3
SAS Label:
The volume of urine collection #3
English Text:
The volume of urine collection #3
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 388 Range of Values 92 92
. Missing 8499 8591

URDFLOW3 - Urine #3 Flow Rate

Variable Name:
URDFLOW3
SAS Label:
Urine #3 Flow Rate
English Text:
Urine #3 Flow Rate
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 7.938 Range of Values 87 87
. Missing 8504 8591