Table of Contents

Component Description

The phlebotomy component of NHANES involved the collection of blood specimens. Prior to blood collection, the MEC phlebotomist administered a questionnaire to screen for conditions that would exclude participants from the blood draw. At this time, fasting status was determined. Blood specimens for basic hematology, nutritional biochemistry, and special studies were obtained.

Blood specimens were collected on participants aged one year and older in the Mobile Examination Center (MEC).

Eligible Sample

Participants aged 1 year and older were tested.

Description of Laboratory Methodology

The MEC phlebotomist drew blood from the participant’s arm. Participants with hemophilia or who received cancer chemotherapy in the past four weeks or will receive it in the future four weeks were excluded from the venipuncture.

Detailed phlebotomy collection and processing instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM).

See Analytic Notes section for a general description of the fasting questions and calculation of fasting time in hours and minutes since the survey participant last ate or drank anything and the time of venipuncture draw.

Data Processing and Editing

Phlebotomy data were recorded directly into a computerized database; all forms used in the MEC were automated.

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 Laboratory/Medical Technologists Procedures Manual (LPM).

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.

Use PHAFSTHR and PHAFSTMN to determine the duration of fasting in hours and minutes, respectively. When calculating a fasting time in hours and minutes, pay careful attention to the other times in hours and minutes. For example, the survey participants were asked: "When was the last time you ate or drank anything other than plain water? Do not include diet soda or black coffee or tea with artificial sweeteners like Sweet'N Low, NutraSweet, Equal, or Splenda." Survey participants were then asked questions PHQ020 to PHQ060: "Have you had any of the following since the last time you ate or drank anything other than plain water? Coffee or tea with cream or sugar (Include milk or non-dairy creamers); Alcohol, such as beer, wine, or liquor; Gum, breath mints, lozenges, cough drops, or cold remedies; Antacids, laxatives, or anti-diarrheal; Dietary supplements such as vitamins and minerals."

If you are using fasting status in any of your analyses, please consider the answers to PHACOFHR/PHACOFMN, PHAALCHR/PHAALCMN, PHAGUMHR/PHAGUMMN/ PHAANTHR/PHAANTMN, and PHASUPHR/PHASUPMN with the times in hours and minutes in addition to the PHAFSTHR and PHSFSTMN times.

Use PHDSESN to determine the session in which the participant was examined.

MEC 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

PHQ020 - Coffee or tea with cream or sugar?

Variable Name:
PHQ020
SAS Label:
Coffee or tea with cream or sugar?
English Text:
Coffee or tea with cream or sugar? [Include milk or non-dairy creamers.]
English Instructions:
Have you had any of the following since " today at" or "yesterday at" fasting time in PHQ010.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 25 25
2 No 8807 8832
. Missing 475 9307

PHACOFHR - Coffee/tea fast time (hours)

Variable Name:
PHACOFHR
SAS Label:
Coffee/tea fast time (hours)
English Text:
The time (in hours) since the examinee last drank coffee or tea with cream or sugar.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 12 Range of Values 25 25
. Missing 9282 9307

PHACOFMN - Coffee/tea fast time (minutes)

Variable Name:
PHACOFMN
SAS Label:
Coffee/tea fast time (minutes)
English Text:
The time (in minutes) since the examinee last drank coffee or tea with cream or sugar.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2 to 58 Range of Values 25 25
. Missing 9282 9307

PHQ030 - Alcohol, such as beer, wine, or liquor?

Variable Name:
PHQ030
SAS Label:
Alcohol, such as beer, wine, or liquor?
English Text:
Alcohol, such as beer, wine, or liquor?
English Instructions:
Have you had any of the following since "today at" or "yesterday at" the fasting time in PHQ010.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 7 7
2 No 8825 8832
. Missing 475 9307

PHAALCHR - Alcohol fast time (hours)

Variable Name:
PHAALCHR
SAS Label:
Alcohol fast time (hours)
English Text:
The time (in hours) the examinee last drank alcohol such as beer, wine, or liquor.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 to 15 Range of Values 7 7
. Missing 9300 9307

PHAALCMN - Alcohol fast time (minutes)

Variable Name:
PHAALCMN
SAS Label:
Alcohol fast time (minutes)
English Text:
The time (in minutes) the examinee last drank alcohol such as beer, wine, or liquor.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3 to 42 Range of Values 7 7
. Missing 9300 9307

PHQ040 - Gum, mints, lozenges or cough drops

Variable Name:
PHQ040
SAS Label:
Gum, mints, lozenges or cough drops
English Text:
Gum, breath mints, lozenges or cough drops, or other cough or cold remedies?
English Instructions:
Have you had any of the following since "today at" or "yesterday at" the fasting time in PHQ010?
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 88 88
2 No 8744 8832
. Missing 475 9307

PHAGUMHR - Gum, mints cough drops fast time (hours)

Variable Name:
PHAGUMHR
SAS Label:
Gum, mints cough drops fast time (hours)
English Text:
The time (in hours) the examinee last had gum, breath mints, lozenges or cough drops, or other cough or cold remedies.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 15 Range of Values 88 88
. Missing 9219 9307

PHAGUMMN - Gum, mints, cough fast time (minutes)

Variable Name:
PHAGUMMN
SAS Label:
Gum, mints, cough fast time (minutes)
English Text:
The time (in minutes) the examinee last had gum, breath mints, lozenges or cough drops, or other cough or cold remedies.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 to 57 Range of Values 88 88
. Missing 9219 9307

PHQ050 - Antacids, laxatives, or anti-diarrheals?

Variable Name:
PHQ050
SAS Label:
Antacids, laxatives, or anti-diarrheals?
English Text:
Antacids, laxatives, or anti-diarrheals?
English Instructions:
Have you had any of the following since "today at" or "yesterday at" the fasting time in PHQ010.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 5 5
2 No 8827 8832
. Missing 475 9307

PHAANTHR - Antacids, laxatives fast time (hours)

Variable Name:
PHAANTHR
SAS Label:
Antacids, laxatives fast time (hours)
English Text:
The time (in hours) the examinee last had antacids, laxatives or anti-diarrheals.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 8 Range of Values 5 5
. Missing 9302 9307

PHAANTMN - Antacids, laxatives fast time (minutes)

Variable Name:
PHAANTMN
SAS Label:
Antacids, laxatives fast time (minutes)
English Text:
The time (in minutes) the examinee last had antacids, laxatives or anti-diarrheals.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
9 to 30 Range of Values 5 5
. Missing 9302 9307

PHQ060 - Dietary supplements?

Variable Name:
PHQ060
SAS Label:
Dietary supplements?
English Text:
Dietary supplements such as vitamins and minerals? [Include multivitamins and single nutrient supplements.]
English Instructions:
Have you had any of the following since "today at" or "yesterday at" the fasting time in PHQ010.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 16 16
2 No 8816 8832
. Missing 475 9307

PHASUPHR - Dietary supplements fast time (hours)

Variable Name:
PHASUPHR
SAS Label:
Dietary supplements fast time (hours)
English Text:
The time (in hours) the examinee last had dietary supplements such as vitamins and minerals.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 11 Range of Values 16 16
. Missing 9291 9307

PHASUPMN - Dietary supplements fast time (minutes)

Variable Name:
PHASUPMN
SAS Label:
Dietary supplements fast time (minutes)
English Text:
The time (in minutes) the examinee last had dietary supplements such as vitamins and minerals.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 58 Range of Values 16 16
. Missing 9291 9307

PHAFSTHR - Total length of "food fast," hours

Variable Name:
PHAFSTHR
SAS Label:
Total length of "food fast," hours
English Text:
The time (in hours) between when the examinee last ate or drank anything other than water and the time of the venipuncture.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 52 Range of Values 8832 8832
. Missing 475 9307

PHAFSTMN - Total length of "food fast," minutes

Variable Name:
PHAFSTMN
SAS Label:
Total length of "food fast," minutes
English Text:
The time (in minutes) between when the examinee last ate or drank anything other than water and the time of the venipuncture.
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 59 Range of Values 8832 8832
. Missing 475 9307

PHDSESN - Session in which SP was examined

Variable Name:
PHDSESN
SAS Label:
Session in which SP was examined
English Text:
Session in which SP was examined
Target:
Both males and females 1 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 morning 4311 4311
1 afternoon 3356 7667
2 evening 1640 9307
. Missing 0 9307