The analysis of biological samples for markers of physiological and nutritional status has challenged scientists for decades. It is a time-consuming process requiring precision and accuracy. Nutritional Biomarker Analysis (NBA) provides core analytical support for HNR and its collaborators, both national and international.
All assays within NBA are calibrated using commercially available standard reference materials. Where available, we participate in nationally and internationally organised quality assurance schemes.
NBA has two sections Clinical Chemistry & Chromatography.
Clinical Chemistry
Automated analysis
NBA performs analysis on plasma, serum or urine using fully automated instruments. Concentrations of analytes measured are commonly in the mmol-µmol per litre range.
Analytes include:
- glucose
- lipids
- electrolytes
- liver, renal and bone profiles
- markers of acute phase response: CRP, haptoglobin, AGP,
- iron, total iron binding capacity
- 25OH vitamin D
Immunoassay
Immunoassays make use of the binding between an antigen and its antibody in order to identify and quantify the specific antigen in a sample. Immunoassays may be competitive or non-competitive, instrumental (Siemens ProSpec, Dimension) or ELISA Immunoassays are a rapid yet specific method for measuring analytes in the nmol-pmol per litre range.
Analytes currently being measured frequently by NBA using immunoassay techniques include:
- Iron status: soluble transferrin receptor, ferritin
- Homocysteine
- Urinary “micro” albumin
Immunoassays for other analytes can be set up as required – please enquire.
Manual Techniques
A number of analytes measured are specific to nutritional based research. Often commercialassays are not available and it is necessary to develop, optimise and characterise the assays for our own use.
Examples of such analytical techniques used here are:
- Gut permeability (lactulose:mannitol ratios)
- para-amino benzoic acid (PABA)
- vitamin C
- vitamin B1 status (transketolase activation coefficient)
- vitamin B2 status (glutathione reductase activation coefficient).
Chromatography
The Chromatography team uses HPLC and GC techniques to determine nutritional biomarkers
Gas chromatography (GC)
HNR boasts fully automated methods for the GC(FID), analysis of derivatized fatty acids in the following human tissues:
- Plasma
- erythrocyte membranes
- platelets
- breast milk
- adipose tissue
- liver
- myocardial membranes
- buccal cells
High-Performance Liquid Chromatography (HPLC)
HPLC methods have been established for analysis of fat and water-soluble vitamins in plasma.
Simultaneous fat soluble vitamin analysis of:
- Vitamin A (total retinol)
- Vitamin E (alpha- and
- gamma-tocopherol)
- carotenoids:
- lutein
- alpha- and beta-cryptoxanthin
- lycopene
- alpha- and beta-carotene
Vitamin K, as phylloquinone, can be analysed using fluorescence detection.
Water soluble vitamin analysis:
- Vitamin B6, as pyridoxal phosphate and pyridoxic acid (using fluorescencedetection).