Tag Archives: Nutrition

New Resources Provide Updated Guidance on Biomarker Collection in DHS-8

The DHS Program is pleased to announce the availability of the Biomarker Manual: Training Program for Measuring and Testing for Biomarkers and the DHS Height Standardization Tool on The DHS Program website.

The Biomarker Manual aligns with DHS-8 standard materials and policies representing the most up-to-date procedures. Standard measures in DHS surveys include height/length, weight, and hemoglobin. Anthropometric data are collected for children age 0-59 months, women age 15-49, and men age 15-49, 15-54, or 15-59 depending on the survey. These data are used to estimate malnutrition in children, body mass index (BMI) in adults, and BMI-for-age in adolescents. Hemoglobin measurement provides anemia prevalence estimates for children age 6-59 months along with women and men.

Measurements fromBiomarkers collectedIndicators reported
Children age 0-59 months


Children age 6-59 months
Height/length

Weight

Hemoglobin
-Malnutrition in children





-Anemia prevalence
Women age 15-49

Men age 15-49, 15-54, or 15-59
Height

Weight

Hemoglobin
-BMI in adults

-BMI-for-age in adolescents (age 15-19)



-Anemia prevalence

The Biomarker Manual is a critical resource used by DHS Program biomarker specialists and consultants to train biomarker technicians and supervisors on all aspects of collecting high-quality biomarker data. The Biomarker Manual can serve as a tool for others conducting surveys similar to DHS surveys. The manual includes procedures for:

  • Completing The DHS Program Biomarker Questionnaire and related documentation
  • Anthropometric measurement
  • Capillary blood collection
  • Hemoglobin measurement
  • Biohazardous waste management and disposal
Example of an informational pamphlet in the Biomarker Manual

The Biomarker Manual also includes examples of materials to aid in data collection – informational pamphlets provided to households, referral forms provided for cases of severe acute malnutrition and severe anemia, forms used during training on anthropometry (e.g., standardization exercises), and forms for monitoring equipment during fieldwork (daily maintenance logs).

The DHS Height Standardization Tool is used during the anthropometry standardization exercise to record trainees’ height or length measurements and to calculate trainees’ accuracy and precision. The results of the calculations are illustrated visually for each trainee and compared to the pass/fail cutoffs for accuracy and precision. The tool is a useful resource for anyone collecting anthropometry data in surveys or research as it helps to identify trainees who may need further training and re-standardization before data collection. 

Many DHS surveys collect additional biomarkers in addition to the standard biomarkers mentioned above, e.g., malaria rapid diagnostic testing (RDT), dried blood spot (DBS) preparation for lab-based testing for a variety of infections or conditions, blood pressure measurement, and micronutrient biomarkers. The resources in the new Biomarker Manual can be adapted to accommodate the collection of these other biomarkers.



Collecting Quality Anthropometric Data in The DHS Program

The DHS Program has been a leading source of anthropometric (height and weight) data for more than 30 years. Measurements are collected from children, women, and men in some surveys. This information enables countries to make data-driven decisions and to monitor their progress in improving nutritional status and achieving the Sustainable Development Goals.

The DHS Program continually improves anthropometric data collection processes. In 2018, The DHS Program undertook a qualitative study to identify how to further enhance the quality of anthropometry data. The findings prompted several tools and processes to be tested in the field in Nigeria, including biomarker checklists and anthropometry remeasurement, which have now become standard practice.

Here are some examples of how The DHS Program supports countries to collect quality anthropometric data.

Designing surveys that incorporate best practices for collecting anthropometric data

To increase knowledge and enhance capacity of countries to implement DHS surveys, The DHS Program provides technical assistance on anthropometric data collection. An anthropometry brochure summarizes the key inputs needed to collect quality anthropometric data. It is based on the recently released WHO-UNICEF guidelines for anthropometric data collection.  

Training fieldworkers to take precise and accurate measurements

DHS Program staff participate in an in-house standardization exercise to become gold standard measurers. © 2019 Valene Bia, ICF

DHS anthropometry trainings are interactive, including standardization exercises. Trainees take two separate measurements of multiple children which are compared to those of a gold standard measurer. Staff at The DHS Program, consultants, and in-country trainers have been certified as gold standard measurers. These data are entered into the DHS Anthropometry Standardization Tool to identify trainees who need re-training and re-standardization.

Monitoring and improving anthropometric data in real-time

During data collection, field check tables are run, summarizing recently collected data that reflect team performance. If problems are discovered, feedback is provided to data collection supervisors. The DHS Anthropometry Field Check Tables are based on years of experience and analytical studies.

The DHS Program has also implemented new height and weight re-measurement procedures, in which repeat measurements are taken for a random set of children and from children with an unusual first measurement. During field work, the Computer-Assisted Personal Interviewing (CAPI) system produces a report on children selected for remeasurement. This provides information on overall anthropometry data quality and reduces the number of incorrect measurements.

Conducting data entry in the field. © ICF

Communicating quality of anthropometric data to users

Information on anthropometric data collection and quality helps users have confidence in the results and make correct inferences when comparing estimates over time and across countries. Recent DHS survey final reports provide a summary of anthropometric data quality in addition to documentation on survey implementation. For more in-depth information on data quality, DHS datasets can be inputted into the WHO Anthro Survey Analyser.

Data quality procedures lead to high quality anthropometry data for children in Nigeria
97% of trainees passed the standardization exercise
Nearly all trainees passed the standardization accuracy and precision criteria.
Only 2% of random remeasurement cases had a height difference > 1 cm
Data collectors’ precision for height measurements was high.
< 1% of data were implausible for each anthropometric index
This meets the WHO-UNICEF data quality criteria of < 1% implausible values based on WHO Growth Standards.
< 1% missing data for month and year of birth
Completeness of date of birth data was high.
< 3% missing data for height and weight measurements
There does not appear to be selection bias in height and weight data collection.

Data quality is an iterative process. As The DHS Program continues to learn, further enhancements and innovations will be implemented to ensure quality anthropometric data.

Featured image: © 2018 Arturo Sanabria, Courtesy of Photoshare


The information provided on this Web site is not official U.S. Government information and does not represent the views or positions of the U.S. Agency for International Development or the U.S. Government.

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