Viewing entries in
Biochemical assessment

IZiNCG Practical Tips for collecting blood in the field for assessment of plasma or serum zinc concentration

IZiNCG Practical Tips for collecting blood in the field for assessment of plasma or serum zinc concentration

The second edition of IZiNCG Practical Tips: Collecting blood in the field for assessment of plasma or serum zinc concentration is now available on our website.

The document briefly covers the following topics:

  • Precautions to prevent transmission of infectious agents when handling blood samples 

  • Practices and supplies to avoid zinc contamination of samples 

  • Tips for blood collection technique 

  • Tips for processing samples 

  • Tips for aliquoting of samples in the field laboratory 

  • Tips for sample analyses 

  • Information on reference laboratories

  • Tips for statistical analyses 

  • List of trace element-free blood collection supplies 

  • Image examples of field laboratory hoods

  • Example laboratory protocols for the analysis of plasma/serum zinc by flame atomic absorption spectrophotometry and inductively coupled plasma–optical emission spectrometry (ICP-OES) 

Please contact IZiNCG with any questions or comments regarding this brief.

OpeN-Global: More and better data.

OpeN-Global: More and better data.

February 27, 2019: OpeN-Global, live online

OpeN-Global is a freely available, online resource aimed at supporting the objective, accurate and detailed assessment of nutritional biomarkers from populations globally. In their guest blog for IZiNCG, Drs Jessica Farebrother and Sophie Moore share what OpeN-Global is all about.

OpeN-Global about image.png

OpeN-Global is specifically designed to support and enable work in populations from low- and middle-income countries (LMICs), but the analytical methods presented can be applied to samples from any population group. OpeN-Global additionally provides a network of experts to support the implementation of biomarker assays in laboratories globally, and to help interpret the data obtained. OpeN-Global is an open-access website that is free for all to use.

So what’s it all about?

Malnutrition, from either under- or over-nutrition, affects one in three people globally. This makes malnutrition, together with diet, the biggest risk factors for the global burden of disease - by far.

The recent 2018 Global Nutrition Report stated: “Micronutrient deficiencies are estimated to impact a significant number of people around the world, but there remains far too little information on micronutrient status and deficiencies. More essential information and surveillance need to be gathered to make substantial progress on global targets.”

What’s basically needed, are more and better data.

One of the key barriers to the development of both nutrition-specific and nutrition-sensitive programmes and policies, particularly in LMICs, is the lack of robust evidence on nutritional status in the most vulnerable groups.

Though many health and nutrition related activities in LMICs are underpinned by well-designed national surveys (e.g. the UNICEF Multiple Indicator Cluster Survey), data from the most vulnerable population groups, i.e. infants, children, adolescents, pregnant and lactating women, are often limited to anthropometry and easy-to-assay parameters e.g. haemoglobin, or single micronutrients e.g. vitamin A, iodine.

Other available information may be based on prevalence data, e.g. stunting in under 5’s to assess population risk of zinc deficiency, or household coverage of adequately iodised salt in salt fortification monitoring.

Whilst these proxy measures remain recommended strategies for population nutrition monitoring, a more accurate picture of population nutrient status can be given by biochemical data using human biomarkers.

Stunting prevalence (data) vs Plasma zinc concentration?

Household coverage of iodised salt (salt sample) vs Urinary iodine concentration?

These biochemical assays provide a real picture of nutrient status. Such assays could feature as routine, however are rarely included in demographic and health surveys in LMICs.

What are the barriers to biochemical assessment in population nutrition surveillance?

With the help of our global partner network including leading scientists based in LMICs, we uncovered some of the key barriers to assessment of biochemical samples in LMIC nutrition surveys. And funding was not the only barrier! Our kick-off workshop highlighted several key themes, including:

1. A clear need for guidance and technical support to facilitate the laboratory capabilities in many LMIC settings to support the assessment of a wider panel of nutritional biomarkers than is currently available and routinely used;

2. Excellent research infrastructure and laboratory platforms are in place in many LMIC settings, but several barriers, including staff training opportunities and technical know-how prevents full utilisation.

Support in these key areas would start a positive cycle of quality control and assurance technical accreditation, investment and increased trust – leading to better outputs. More and better data.

Supporting the generation of quality data in-country will support evidence-based policy, and transform nutritional outcomes.

Our response: OpeN-Global

We have established a global network of expertise in nutritional research methodologies. Our 37-strong global partner network of committed academic, technology and industry experts spans 20 institutions across 10 countries on 5 continents.

Through this partnership, we have created OpeN-Global a hub of resource tools to assess nutritional status in global health settings in the form of an open-access website that provides laboratory SOPs to download or signposting to published nutrition assay methods, details on quality control and accreditation, technical support, and fully-referenced general information for over 20 nutrition biomarkers, including key nutrients such as zinc and iodine, to newer technologies and -omics approaches.

And the list is growing.

Our aim: to support the objective, detailed, accurate and high-quality assessment of nutrition biomarkers used in Global Health population surveys and research.

Welcome to OpeN-Global.png


For more information, please contact the project lead, Dr Sophie Moore, Department of Women and Children’s Health, King’s College London on sophie.moore@kcl.ac.uk, or head to www.open-global.kcl.ac.uk from February 27th, and contact us directly from the website.

Al images taken at Medical Research Council The Gambia. Photo credits: Ian Farrell.

Written by Jessica Farebrother and Sophie Moore.

Footnotes:

1 Prevalence of stunting in children under 5 years is a recommended strategy to assess population risk of zinc deficiency. Recommendations of Biomarkers of Nutrition for Development – Zinc, and IZiNCG

2 Assessment of household coverage of iodised salt is a recommended strategy in monitoring and surveillance of relevant salt fortification strategies. Biomarkers of Nutrition for Development - Iodine, and the Iodine Global Network (www.ign.org).

Study in progress: Reference methods for biological sample preparation and zinc analysis

Study in progress: Reference methods for biological sample preparation and zinc analysis

The accurate determination of the prevalence of zinc deficiency is essential for effective design, targeting, and evaluation of interventions. Hence, methodological knowledge gaps are important to understand and address.

The concentration of zinc in biological samples, such as plasma, serum, hair, or urine, varies considerably between populations. While part of this variation is attributable to differences in diet or inflammation – i.e. what we want to measure – part may also be due to the different methods and equipment used to process and analyze the samples. 

Instruments commonly used for zinc analysis include atomic absorption spectrometry (AAS), inductively couple plasma optical (atomic) emission spectrometry (ICP-OES / ICP-AES), and ICP mass spectrometry (ICP-MS). 

IZiNCG has earlier published reference methods for collecting plasma and serum for zinc analysis, but reference methods for sample preparation and zinc analysis have not yet been developed. 

The goals of this project are to:

a)    Establish a set of reference methods for zinc analysis, applicable to new or established laboratories using each major type of instrument; and 

b)    Develop reference data that document analytical accuracy and precision among different instruments and different types of samples under ideal conditions at multiple sites. 

The results, anticipated early-mid 2019, will be communicated as an IZiNCG technical brief following publication in a peer-reviewed scientific journal.

Participating labs:

AAS

University of Colorado Denver, USA

ETH Zurich, Switzerland

Aga Khan University, Pakistan

International Centre for Diarrhoeal Disease Research, Bangladesh

National Institute of Nutrition, Hanoi, Vietnam

ICP-OES

Children’s Hospital Oakland Research Institute, USA

ICP-MS

University of Colorado, Denver, USA

ETH Zurich, Switzerland

Oklahoma State University, USA