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 QA/QC instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM).

Analytic Notes

Refer to the 2011-2012 Laboratory Data Overview for general information on NHANES laboratory data.

The analysis of NHANES 2011-2012 laboratory data must be conducted using the appropriate survey design and demographic variables. The NHANES 2011-2012 Demographics File contains demographic data, health indicators, and other related information collected during household interviews as well as the sample weight variables. The Fasting Questionnaire File includes auxiliary information such as fasting status, the time of venipuncture, and the conditions precluding venipuncture. The demographics and fasting questionnaire files may be linked to the laboratory data file using the unique survey participant identifier (i.e., 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 NHANES Analytic Guidelines and the on-line NHANES Tutorial for further details on the use of sample weights and other analytic issues.

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 71 71
2 No 8457 8528
. Missing 428 8956

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 14 Range of Values 71 71
. Missing 8885 8956

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
0 to 59 Range of Values 71 71
. Missing 8885 8956

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 36 36
2 No 8492 8528
. Missing 428 8956

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
0 to 33 Range of Values 36 36
. Missing 8920 8956

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
0 to 59 Range of Values 36 36
. Missing 8920 8956

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 277 277
2 No 8251 8528
. Missing 428 8956

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 16 Range of Values 277 277
. Missing 8679 8956

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
0 to 59 Range of Values 277 277
. Missing 8679 8956

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 23 23
2 No 8505 8528
. Missing 428 8956

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 18 Range of Values 23 23
. Missing 8933 8956

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
5 to 53 Range of Values 23 23
. Missing 8933 8956

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 71 71
2 No 8457 8528
. Missing 428 8956

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 24 Range of Values 71 71
. Missing 8885 8956

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 59 Range of Values 71 71
. Missing 8885 8956

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 36 Range of Values 8528 8528
. Missing 428 8956

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 8528 8528
. Missing 428 8956

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 4233 4233
1 afternoon 3294 7527
2 evening 1429 8956
. Missing 0 8956