Table of Contents

Component Description

The objectives of this component are to:
1) Provide data for monitoring secular trends in measures of nutritional status in the U.S. population;
2) Evaluate the effect of people's habits and behaviors such as physical activity and the use of alcohol, tobacco, and dietary supplements on people's nutritional status; and
3) Evaluate the effect of changes in nutrition and public health policies - including welfare reform legislation, food fortification policy, and child nutrition programs - on the nutritional status of the U.S. population.

These data will be used to estimate deficiencies and toxicities of specific nutrients in the population and subgroups, to provide population reference data, and to estimate the contribution of diet, supplements, and other factors to Whole Blood levels of nutrients. Data will be used for research to further define nutrient requirements as well as optimal levels for disease prevention and health promotion.

Eligible Sample

Participants aged 1 year and over were tested.

Description of Laboratory Methodology

Blood specimens were measured at the NHANES MECs. Detailed specimen collection and processing instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM).

The methods used to derive CBC parameters are based on the Beckman Coulter method of counting and sizing, in combination with an automatic diluting and mixing device for sample processing, and a single beam photometer for hemoglobinometry. The WBC differential uses VCS technology. See Chapter 7 of the NHANES Laboratory/Medical Technologists Procedures Manual (LPM) for details.

The Beckman Coulter MAXM instrument in the Mobile Examination Centers (MECs) produces a complete blood count on blood specimens and provides a distribution of blood cells for all participants.

There were no changes to the lab methods, or lab site from the previous 2 years. There was a change to the lab instrument from 2005-2006 to 2007-2008. In 2005-2006 the Beckman Coulter MAXM was used and in 2007-2008 the Beckman Coulter HMX was used. There are no basic changes in the principles of the instruments.

A detailed description of the laboratory method used can be found on the NHANES website.

Data Processing and Editing

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

Five derived variables were created in this data file. The formula for their derivation is as follows:
LBDLYMNO = LBXWBCSI * LBXLYPCT/100 (round to 1 decimal)
LBDMONO = LBXWBCSI * LBXMOPCT/100 (round to 1 decimal)
LBDNENO = LBXWBCSI * LBXNEPCT /100 (round to 1 decimal)
LBDEONO = LBXWBCSI * LBXEOPCT/100 (round to 1 decimal)
LBDBANO = LBXWBCSI * LBXBAPCT/100 (round to 1 decimal)

Laboratory Quality Assurance and Monitoring

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

A detailed description of the quality assurance and quality control procedures can be found on the NHANES website.

Analytic Notes

The analysis of NHANES 2007–2008 laboratory data must be conducted with the key survey design and basic demographic variables. The NHANES 2007–2008 Household Questionnaire Data Files contain demographic data, health indicators, and other related information collected during household interviews. They also contain all survey design variables and sample weights for these age groups. The phlebotomy file includes auxiliary information such as the conditions precluding venipuncture. The household questionnaire and phlebotomy 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 Analytic Guidelines for further details on the use of sample weights and other analytic issues. The Analytic Guidelines are available on the NHANES website.

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

LBXWBCSI - White blood cell count (1000 cells/uL)

Variable Name:
LBXWBCSI
SAS Label:
White blood cell count (1000 cells/uL)
English Text:
White blood cell count: SI
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.5 to 83.2 Range of Values 8266 8266
. Missing 1041 9307

LBXLYPCT - Lymphocyte percent (%)

Variable Name:
LBXLYPCT
SAS Label:
Lymphocyte percent (%)
English Text:
Lymphocyte percent (%)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
4.9 to 85.5 Range of Values 8250 8250
. Missing 1057 9307

LBXMOPCT - Monocyte percent (%)

Variable Name:
LBXMOPCT
SAS Label:
Monocyte percent (%)
English Text:
Monocyte percent (%)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.7 to 44.5 Range of Values 8250 8250
. Missing 1057 9307

LBXNEPCT - Segmented neutrophils percent (%)

Variable Name:
LBXNEPCT
SAS Label:
Segmented neutrophils percent (%)
English Text:
Segmented neutrophils percent (%)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5.3 to 92.1 Range of Values 8250 8250
. Missing 1057 9307

LBXEOPCT - Eosinophils percent (%)

Variable Name:
LBXEOPCT
SAS Label:
Eosinophils percent (%)
English Text:
Eosinophils percent (%)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 28.5 Range of Values 8250 8250
. Missing 1057 9307

LBXBAPCT - Basophils percent (%)

Variable Name:
LBXBAPCT
SAS Label:
Basophils percent (%)
English Text:
Basophils percent (%)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 15.9 Range of Values 8250 8250
. Missing 1057 9307

LBDLYMNO - Lymphocyte number (1000 cells/uL)

Variable Name:
LBDLYMNO
SAS Label:
Lymphocyte number (1000 cells/uL)
English Text:
Lymphocyte number (1000 cells/uL)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.4 to 71.1 Range of Values 8249 8249
. Missing 1058 9307

LBDMONO - Monocyte number (1000 cells/uL)

Variable Name:
LBDMONO
SAS Label:
Monocyte number (1000 cells/uL)
English Text:
Monocyte number (1000 cells/uL)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.1 to 5.5 Range of Values 8249 8249
. Missing 1058 9307

LBDNENO - Segmented neutrophils num (1000 cell/uL)

Variable Name:
LBDNENO
SAS Label:
Segmented neutrophils num (1000 cell/uL)
English Text:
Segmented neutrophils num (1000 cell/uL)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.2 to 20.5 Range of Values 8249 8249
. Missing 1058 9307

LBDEONO - Eosinophils number (1000 cells/uL)

Variable Name:
LBDEONO
SAS Label:
Eosinophils number (1000 cells/uL)
English Text:
Eosinophils number (1000 cells/uL)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 2.9 Range of Values 8249 8249
. Missing 1058 9307

LBDBANO - Basophils number (1000 cells/uL)

Variable Name:
LBDBANO
SAS Label:
Basophils number (1000 cells/uL)
English Text:
Basophils number (1000 cells/uL)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 2.1 Range of Values 8249 8249
. Missing 1058 9307

LBXRBCSI - Red blood cell count (million cells/uL)

Variable Name:
LBXRBCSI
SAS Label:
Red blood cell count (million cells/uL)
English Text:
Red cell count SI
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2.49 to 6.97 Range of Values 8267 8267
. Missing 1040 9307

LBXHGB - Hemoglobin (g/dL)

Variable Name:
LBXHGB
SAS Label:
Hemoglobin (g/dL)
English Text:
Hemoglobin (g/dL)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7.5 to 19.7 Range of Values 8267 8267
. Missing 1040 9307

LBXHCT - Hematocrit (%)

Variable Name:
LBXHCT
SAS Label:
Hematocrit (%)
English Text:
Hematocrit (%)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
22.4 to 56.3 Range of Values 8267 8267
. Missing 1040 9307

LBXMCVSI - Mean cell volume (fL)

Variable Name:
LBXMCVSI
SAS Label:
Mean cell volume (fL)
English Text:
Mean cell volume (fL)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
55.9 to 125.3 Range of Values 8267 8267
. Missing 1040 9307

LBXMCHSI - Mean cell hemoglobin (pg)

Variable Name:
LBXMCHSI
SAS Label:
Mean cell hemoglobin (pg)
English Text:
Mean cell hemoglobin (pg)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
18 to 60.8 Range of Values 8267 8267
. Missing 1040 9307

LBXMC - MCHC (g/dL)

Variable Name:
LBXMC
SAS Label:
MCHC (g/dL)
English Text:
Mean cell hemoglobin concentration (g/dL)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
30 to 42.4 Range of Values 8267 8267
. Missing 1040 9307

LBXRDW - Red cell distribution width (%)

Variable Name:
LBXRDW
SAS Label:
Red cell distribution width (%)
English Text:
Red cell distribution width (%)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
6.3 to 37.8 Range of Values 8267 8267
. Missing 1040 9307

LBXPLTSI - Platelet count (1000 cells/uL)

Variable Name:
LBXPLTSI
SAS Label:
Platelet count (1000 cells/uL)
English Text:
Platelet count (%) SI
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
28 to 1000 Range of Values 8267 8267
. Missing 1040 9307

LBXMPSI - Mean platelet volume (fL)

Variable Name:
LBXMPSI
SAS Label:
Mean platelet volume (fL)
English Text:
Mean platelet volume (fL)
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5.1 to 12.6 Range of Values 8267 8267
. Missing 1040 9307