Table of Contents

Component Description

See the general documentation on second day laboratory exams.

Also, see the documentation for the primary exam data for Laboratory 25 (HE). The Beckman Coulter® MAXM instrument in the MEC produces a complete blood count on blood specimens and provides a distribution of blood cells for all participants.

Eligible Sample

Participants aged 16-69 years who do not meet any of the exclusion criteria are eligible. 

Description of Laboratory Methodology

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 for details.

Data Processing and Editing

Blood specimens were measured at the NHANES Mobile Examination Centers. Detailed specimen collection and processing instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM). Read the LABDOC file for detailed data processing and editing protocols. The analytical methods are described in the Description of the Laboratory Methodology section.

Laboratory Quality Assurance and Monitoring

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

Analytic Notes

The second day exam data was a convenience sample and thus did not have sample weights. The analysis of NHANES laboratory data must be conducted with the key survey design and basic demographic variables. The NHANES Household Questionnaire Data files contain demographic data, health indicators, and other related information collected during household interviews.  The Phlebotomy Examination file includes auxiliary information such as the conditions precluding venipuncture. The Household Questionnaire and Phlebotomy Examination files may be linked to the laboratory data file using the unique survey participant identifier SEQN.

Derived variables were created using the following calculation:
LB2LYMNO = LB2WBCSI * LB2LYPCT/100
LB2MONO = LB2WBCSI * LB2MOPCT/100
LB2NENO = LB2WBCSI * LB2NEPCT/100
LB2EONO = LB2WBCSI * LB2EOPCT/100
LB2BANO = LB2WBCSI * LB2BAPCT/100

The five count variables are:
Segmented neutrophils number (LB2NENO)
Lymphocyte number (LB2LYMNO)
Monocyte number (LB2MONO)
Eosinophil number (LB2EONO)
Basophil number (LB2BANO)

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 16 YEARS - 69 YEARS

LB2DAY - Days between first and second exam

Variable Name:
LB2DAY
SAS Label:
Days between first and second exam
English Text:
Days between first and second exam
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3 to 47 Range of Values 551 551
. Missing 6 557

LB2WBCSI - White blood cell count (1000 cells/uL)

Variable Name:
LB2WBCSI
SAS Label:
White blood cell count (1000 cells/uL)
English Text:
White blood cell count (1000 cells/uL)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2.6 to 15.9 Range of Values 551 551
. Missing 6 557

LB2LYPCT - Lymphocyte percent (%)

Variable Name:
LB2LYPCT
SAS Label:
Lymphocyte percent (%)
English Text:
Lymphocyte percent (%)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7.5 to 65.8 Range of Values 551 551
. Missing 6 557

LB2MOPCT - Monocyte percent (%)

Variable Name:
LB2MOPCT
SAS Label:
Monocyte percent (%)
English Text:
Monocyte percent (%)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2.4 to 21.1 Range of Values 551 551
. Missing 6 557

LB2NEPCT - Segmented neutrophils percent (%)

Variable Name:
LB2NEPCT
SAS Label:
Segmented neutrophils percent (%)
English Text:
Segmented neutrophils percent (%)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
25 to 86.3 Range of Values 551 551
. Missing 6 557

LB2EOPCT - Eosinophils percent (%)

Variable Name:
LB2EOPCT
SAS Label:
Eosinophils percent (%)
English Text:
Eosinophils percent (%)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.1 to 29.7 Range of Values 551 551
. Missing 6 557

LB2BAPCT - Basophils percent (%)

Variable Name:
LB2BAPCT
SAS Label:
Basophils percent (%)
English Text:
Basophils percent (%)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 7.9 Range of Values 551 551
. Missing 6 557

LB2LYMNO - Lymphocyte number (1000 cells/uL)

Variable Name:
LB2LYMNO
SAS Label:
Lymphocyte number (1000 cells/uL)
English Text:
Lymphocyte number (1000 cells/uL)
Target:
Both males and females 16 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.5 to 6.9 Range of Values 551 551
. Missing 6 557

LB2MONO - Monocyte number (1000 cells/uL)

Variable Name:
LB2MONO
SAS Label:
Monocyte number (1000 cells/uL)
English Text:
Monocyte number (1000 cells/uL)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.1 to 1.5 Range of Values 551 551
. Missing 6 557

LB2NENO - Segmented neutrophils num (1000 cell/uL)

Variable Name:
LB2NENO
SAS Label:
Segmented neutrophils num (1000 cell/uL)
English Text:
Segmented neutrophils num (1000 cell/uL)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.9 to 12 Range of Values 551 551
. Missing 6 557

LB2EONO - Eosinophils number (1000 cells/uL)

Variable Name:
LB2EONO
SAS Label:
Eosinophils number (1000 cells/uL)
English Text:
Eosinophils number (1000 cells/uL)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 2.1 Range of Values 551 551
. Missing 6 557

LB2BANO - Basophils number (1000 cells/uL)

Variable Name:
LB2BANO
SAS Label:
Basophils number (1000 cells/uL)
English Text:
Basophils number (1000 cells/uL)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 0.5 Range of Values 551 551
. Missing 6 557

LB2RBCSI - Red blood cell count (million cells/uL)

Variable Name:
LB2RBCSI
SAS Label:
Red blood cell count (million cells/uL)
English Text:
Red blood cell count (million cells/uL)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3.06 to 6.51 Range of Values 551 551
. Missing 6 557

LB2HGB - Hemoglobin (g/dL)

Variable Name:
LB2HGB
SAS Label:
Hemoglobin (g/dL)
English Text:
Hemoglobin (g/dL)
Target:
Both males and females 16 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
8.3 to 19.1 Range of Values 551 551
. Missing 6 557

LB2HCT - Hematocrit (%)

Variable Name:
LB2HCT
SAS Label:
Hematocrit (%)
English Text:
Hematocrit (%)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
26.9 to 56.2 Range of Values 551 551
. Missing 6 557

LB2MCVSI - Mean cell volume (fL)

Variable Name:
LB2MCVSI
SAS Label:
Mean cell volume (fL)
English Text:
Mean cell volume (fL)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
60 to 102.8 Range of Values 551 551
. Missing 6 557

LB2MCHSI - Mean cell hemoglobin (pg)

Variable Name:
LB2MCHSI
SAS Label:
Mean cell hemoglobin (pg)
English Text:
Mean cell hemoglobin (pg)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
18.4 to 35.6 Range of Values 551 551
. Missing 6 557

LB2MC - MCHC (g/dL)

Variable Name:
LB2MC
SAS Label:
MCHC (g/dL)
English Text:
MCHC (g/dL)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
30.1 to 35.7 Range of Values 551 551
. Missing 6 557

LB2RDW - Red cell distribution width (%)

Variable Name:
LB2RDW
SAS Label:
Red cell distribution width (%)
English Text:
Red cell distribution width (%)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
11.1 to 21.9 Range of Values 551 551
. Missing 6 557

LB2PLTSI - Platelet count (1000 cells/uL)

Variable Name:
LB2PLTSI
SAS Label:
Platelet count (1000 cells/uL)
English Text:
Platelet count (1000 cells/uL)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
51 to 551 Range of Values 551 551
. Missing 6 557

LB2MPSI - Mean platelet volume (fL)

Variable Name:
LB2MPSI
SAS Label:
Mean platelet volume (fL)
English Text:
Mean platelet volume (fL)
Target:
Both males and females 16 YEARS - 69 YEARS
Code or Value Value Description Count Cumulative Skip to Item
6.2 to 11.4 Range of Values 551 551
. Missing 6 557