Vitamins, Trace Elements & Nutrition Labs

Convert whole blood cadmium between µg/L, nmol/L and µg/dL, against separate reference values for smokers and non-smokers.

Convert blood lead between µg/dL, µg/L, µmol/L and nmol/L, and read the result against the CDC reference value and the standard action levels.

Convert whole blood mercury between µg/L, nmol/L and µg/dL, and read the result against the general-population upper limit.

Calculate the Geriatric Nutritional Risk Index from serum albumin, weight and height, with the original risk bands and what the score is really measuring.

Calculate 24-hour nitrogen balance from protein intake and urine urea nitrogen, and see what makes the answer unreliable.

Calculate Onodera’s Prognostic Nutritional Index from serum albumin and total lymphocyte count, with the original surgical cut-offs and what they do and do not mean.

Convert red cell folate between ng/mL, µg/L and nmol/L, and see why the result reflects the preceding four months rather than the last meal.

Convert urine urea nitrogen between mg/dL, mmol/L and g/L, and keep urea nitrogen and urea itself apart.

Convert vitamin A from international units to micrograms of retinol activity equivalent, using the correct factor for retinol, supplemental beta-carotene or dietary carotenoids.

Convert serum vitamin B12 between pg/mL, ng/L and pmol/L, and see why a normal result does not exclude deficiency.

Convert total 25-hydroxyvitamin D between ng/mL, nmol/L and µg/L, with the deficiency tiers and an honest account of the contested sufficiency threshold.

Convert vitamin E from international units to milligrams of alpha-tocopherol, using the correct factor for the natural or the synthetic form.

Calculate the serum zinc to copper ratio, and see why it is an orientation aid rather than a validated cut-off — and why inflammation makes it unreliable.