Table of Contents

Component Description

Sera from stored surplus specimens in the NHANES 1999-2004 cycles were tested for NT-proBNP.

Eligible Sample

NHANES participants aged 1 year or older who consented to storing their samples for future research and had stored samples from 1999-2004.

Description of Laboratory Methodology

This stored specimen study was conducted by the Principal Investigator (PI) Dr. Elizabeth Selvin at the Johns Hopkins Bloomberg School of Public Health. All measurements were performed during 2018-2020 at the University of Maryland School of Medicine, Baltimore, Maryland (Lab Director: Dr. Robert Christenson).

NT-proBNP
NT-proBNP (Roche Diagnostics) was measured in serum on the Roche e611 autoanalyzer. The lower and upper limits of detection are (5 pg/ml, 35000 pg/ml).

CVs: 3.1% (low, 46 pg/ml) and 2.7% (high, 32805 pg/ml)

The NT-proBNP result is expressed as pg/ml.

Data Processing and Editing

Data were received after all analyses were complete. The data were not edited.
Data Access: All data are publicly available.

Analytic Notes

Refer to the 1999-2000, 2001-2002, and 2003-2004 Laboratory Data Overview for general information on NHANES laboratory data. For information on the stored specimens, refer to the NHANES Biospecimen Program.

Detection Limits
The detection limits were constant. The variable name ending in “L” (ex., SSBNPL) indicates whether the result was either measurable, below the lower limit of detection (LLOD) or above the upper limit of detection (ULOD): A “0” value means that the result was measurable. A “1” indicates that the result was below the LLOD. A “2” indicates that the result was above the ULOD. For analytic results below the limit of detection (ex., SSBNPL=1), an imputed fill value was placed in the analyte results field. This value is the limit of detection divided by square root of 2 (LOD/√2).  For analytic results above the limit of detection (ex., SSBNPL=2), an imputed fill value equal to the value of the ULOD was placed in the analyte results field.

The variable prefixed SS (ex., SSBNP) provides the analytic result.

An indicator variable (SSPRIS) is included for whether the analyte was measured in a pristine sample (never thawed): 0=non-pristine; 1=pristine.

The limits of detection (LODs) for NT-proBNP are:

Variable Name

Description

LODs

SSBNP

NT-proBNP, pg/ml

5 pg/ml, 35000 pg/ml

Variable Name

Description

SSBNPL

NT-proBNP comment code

SSPRIS

Pristine sample


Subsample Weights

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 (WTSSCB2Y, WTSSCB4Y). 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. These sample weights are shared with file: “SSCARD_A”, which was from the same sample of survey participants.

The work was funded by a grant (PI: Elizabeth Selvin) received by the Johns Hopkins Bloomberg School of Public Health from the Biomarkers Consortium of the Foundation for the National Institutes of Health (FNIH).

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 1 YEARS - 150 YEARS

WTSSCB2Y - Cardiac biomarkers 2 year weights

Variable Name:
WTSSCB2Y
SAS Label:
Cardiac biomarkers 2 year weights
English Text:
Surplus specimen cardiac biomarkers 2 year weights
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1250.055251 to 297328.56282 Range of Values 21206 21206
0 No lab specimen 0 21206
. Missing 0 21206

WTSSCB4Y - Cardiac biomarker 4 yr weights 1999-2002

Variable Name:
WTSSCB4Y
SAS Label:
Cardiac biomarker 4 yr weights 1999-2002
English Text:
Surplus specimen cardiac biomarker 4 yr weights 1999-2002
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
773.99041 to 117211.18555 Range of Values 14133 14133
0 No lab specimen 0 14133
. Missing 7073 21206

SSBNP - NT-proBNP pg/ml

Variable Name:
SSBNP
SAS Label:
NT-proBNP pg/ml
English Text:
NT-proBNP pg/ml
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3.54 to 35000 Range of Values 21206 21206
. Missing 0 21206

SSBNPL - NT-proBNP comment code

Variable Name:
SSBNPL
SAS Label:
NT-proBNP comment code
English Text:
NT-proBNP comment code
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 Within the detection limits 20480 20480
1 Below lower detection limit 723 21203
2 Above upper detection limit 3 21206
. Missing 0 21206

SSPRIS - Pristine sample

Variable Name:
SSPRIS
SAS Label:
Pristine sample
English Text:
Pristine sample
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 non-pristine 1143 1143
1 pristine 20063 21206
. Missing 0 21206