Table 4.

Blood biomarkers in the UK National Diet and Nutrition Survey Rolling Programe Years 1–11 (2008–19)^a

Measurement	Sample type	Age (years)	Unit	Assay and comments
Full blood count	Whole blood	≥1.5	Multiple	Beckman Coulter LH700 (Years 1–8); Siemens Advia 2120 (Years 8–11). Performed at Addenbrooke's Hospital
HbA1cb	Whole blood	≥1.5	mmol/mol	HPLC (Tosoh Automated Glycohemoglobin Analyser). Years 1–10.
				Performed at Addenbrooke's Hospital
C-reactive protein (CRP)	Serum	≥1.5	mg/L	Siemens Dimension RXL (Years 1–5), Xpand (Years 6–10),
				EXL200 (Year 11) clinical chemistry analysers (manufacturer’s method (extended range)). From Year 11 performed at CBAL
Ferritin	Plasma (Years 1–10), serum Year 11	≥1.5	μg/L	Dade Behring immunonephelometry on Siemens BN ProSpec (Years 1–5), Siemens immunoturbidimetric method on Dimension
				Xpand (Years 6–10), EXL200 (Year 11) clinical chemistry analysers. From Year 11 performed at CBAL
Soluble transferrin receptor (sTfR)	Plasma	≥7	mg/ml	Enzyme immunoassay. Years 1–4
Creatinine	Plasma (Years 1–9), serum Year 10	≥1.5	μmol/L	Siemens Dimension Xpand clinical chemistry analyser (manufacturer’s method). Changed from compensated kinetic Jaffe to enzymatic method during Year 9
Glucose (only if fasted)b	Plasma	≥7	mmol/L	Siemens Dimension Xpand clinical chemistry analyser (manufacturer’s method). Years 1–5
Total and HDL cholesterol, triglycerides	Serum	≥1.5	mmol/L	Siemens Dimension RXL (Years 1–5), Xpand (Years 6–10),
				EXL200 (Year 11) clinical chemistry analysers (manufacturer’s methods). From Year 11 performed at CBAL
LDL cholesterol	Serum	≥1.5	mmol/L	Calculated (Friedewald equation)
Thiamin (vitamin B1)	Red blood cell haemolysates	≥1.5	n/a	ETKAC
Riboflavin (vitamin B2)	Red blood cell haemolysates	≥1.5	n/a	EGRAC
Vitamin B6 (pyridoxal-5-phosphate and pyridoxic acid)	Plasma	≥1.5	nmol/L	HPLC with fluorimetric detection
Vitamin B12	Serum	≥1.5	ng/L	Siemens Advia Centaur (manufacturer’s competitive protein binding method). Performed at Addenbrooke's Hospital
Holo-transcobalamin	Serum	≥1.5	pmol/L	ELISA (Axis Shield Diagnostics, Dundee). Years 6–11
Homocysteine	Plasma	≥7	μmol/L	Immunoturbidimetric assay on Siemens BN ProSpec (manufacturer’s method). Years 1–5
Folate	Serum	≥1.5	nmol/L	LC-MS/MS (During Years 1–6 performed at CDC)
Whole blood folate	Whole blood	≥1.5	nmol/L	Microbiological method, performed at CDC. Red cell folate is calculated from whole blood folate, serum folate and haematocrit.
Vitamin C	Plasma	≥1.5	μmol/L	Fluorescent enzymatic assay
Retinol (vitamin A), retinyl palmitate, α-tocopherol, γ-tocopherol (vitamin E), α- and β-cryptoxanthin, lycopene, lutein and zeaxanthin (combined), α- and β –carotene	Plasma	≥1.5	μmol/L	HPLC with photodiode array detection. Retinyl palmitate measured in Years 1–4 only
Vitamin D (25-hydroxyvitamin D)	Serum	≥1.5	nmol/L	CLIA (DiaSorin Liaison (Years 1–6)). LC-MS/MS (Years 7–11)
Selenium and zinc	Plasma (Years 1–10), serum Year 11	≥7	μmol/L	Inductively coupled plasma mass spectrometry (ICP-MS). From
				Year 11, performed at University Hospital Southampton. Measured in all ages from Year 11
Repository samples	Plasma/serum	≥1.5	n/a

CBAL, Core Biochemical Assay Laboratory, Addenbrooke's Hospital; CDC, Centers for Disease Control; CLIA, Chemiluminescence immunoassay; EGRAC, erythrocyte gluthathione reductase activation coefficient; ELISA, enzyme-linked immunosorbent assay; ETKAC, erythrocyte transketolase activation coefficient; HbA1c, glycated haemoglobin; HDL, high density lipoprotein; HPLC, high performance liquid chromatography; LC-MS/MS, liquid chromatography tandem mass spectrometry; LDL, low density lipoprotein [Friedewald equation: LDL = Total cholesterol – HDL cholesterol – (triglycerides/2.2)].

^aAnalyses were peformed at Medical Research Council Elsie Widdowson Laboratory (Years 1–10) or Nutritional Biomarker Laboratory, MRC Epidemiology Unit (Year 11 onwards) unless otherwise stated.

^bAnalysis of these analytes was funded separately by Diabetes UK.