Vitamins, Trace Elements & Nutrition Labs
Every vitamins, trace elements & nutrition labs calculator on CalcEngines — unit converters, derived indices and interpretive tools, each with its formula, a worked example and the reference intervals it is judged against.
27 calculators in this section
- Biotin (Vitamin B7) Unit ConverterConvert serum biotin between ng/mL, µg/L, nmol/L and pmol/L — and understand the reason the test exists: high-dose biotin interferes with biotin-streptavidin immunoassays, reading falsely high on competitive assays and falsely low on sandwich assays.
- Blood Cadmium Unit ConverterConvert whole blood cadmium between µg/L, nmol/L and µg/dL, against separate reference values for smokers and non-smokers.
- Blood Lead Unit ConverterConvert 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.
- Blood Mercury Unit ConverterConvert whole blood mercury between µg/L, nmol/L and µg/dL, and read the result against the general-population upper limit.
- Copper Unit ConverterConvert serum copper between µg/dL, µmol/L, µg/L and mg/L. Then read it for what it is: nine-tenths of the copper in the sample is bound to caeruloplasmin, so a total copper mostly reports caeruloplasmin, rises as an acute-phase reactant, and can be low, normal or high in Wilson disease.
- Geriatric Nutritional Risk Index (GNRI) CalculatorCalculate the Geriatric Nutritional Risk Index from serum albumin, weight and height, with the original risk bands and what the score is really measuring.
- Niacin (Vitamin B3) Unit ConverterConvert niacin between mg/L, µg/L, ng/mL and µmol/L using nicotinic acid's molecular weight — with a note on why nicotinamide is a different molecule of nearly the same mass, and why niacin status is assessed on urine rather than plasma.
- Nitrogen Balance CalculatorCalculate 24-hour nitrogen balance from protein intake and urine urea nitrogen, and see what makes the answer unreliable.
- Pantothenic Acid (Vitamin B5) Unit ConverterConvert pantothenic acid between mg/L, µg/L, ng/mL and µmol/L — and read the result knowing that isolated vitamin B5 deficiency is essentially unknown in humans and the test is very rarely indicated.
- Prealbumin (Transthyretin) Unit ConverterConvert prealbumin between mg/dL, mg/L and µmol/L — and know two things about it: despite the name it has nothing to do with albumin, and it falls in inflammation independently of nutrition, which is why ASPEN no longer recommend it as a nutrition marker.
- Prognostic Nutritional Index (PNI) CalculatorCalculate 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.
- Red Cell Folate Unit ConverterConvert 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.
- Retinol (Vitamin A) Unit ConverterConvert serum retinol between µg/dL, µmol/L, µg/L and nmol/L, with the WHO deficiency thresholds. Serum retinol is not dietary vitamin A activity: the IU and RAE factors used for intake do not apply to a blood concentration, and confusing the two is the commonest error made with this analyte.
- Riboflavin (Vitamin B2) Unit ConverterConvert plasma riboflavin between µg/L, ng/mL and nmol/L — and read the result knowing that a plasma level mostly reports what the patient ate yesterday, while functional status is measured by the erythrocyte glutathione reductase activation coefficient.
- Serum Folate Unit ConverterConvert serum folate between ng/mL, µg/L and nmol/L. Two things this page will not do: pretend that the 2.266 factor is a molar conversion of what the assay actually measures, and pretend that a normal serum folate excludes deficiency.
- Thiamine (Vitamin B1) Unit ConverterConvert whole-blood thiamine between µg/L, ng/mL and nmol/L using the molecular weight of thiamine diphosphate — the coenzyme the assay actually measures, and the reason a factor taken from free thiamine is 1.6 times wrong.
- Urine Urea Nitrogen Unit ConverterConvert urine urea nitrogen between mg/dL, mmol/L and g/L, and keep urea nitrogen and urea itself apart.
- Vitamin A IU to mcg RAE ConverterConvert vitamin A from international units to micrograms of retinol activity equivalent, using the correct factor for retinol, supplemental beta-carotene or dietary carotenoids.
- Vitamin B12 Deficiency Interpreter: Low, Borderline or Normal B12Decide whether a serum B12 result means deficiency. Enter the B12 and your laboratory's lower limit, the active B12 (holotranscobalamin) and methylmalonic acid if measured, and the context — neurological symptoms, pregnancy, the oral contraceptive, nitrous oxide, metformin, acid suppression, a vegan diet — and the page says whether deficiency is likely, indeterminate or unlikely on the BSH 2014 and NICE 2024 guidelines, and where a normal result must not stop treatment.
- Vitamin B12 Unit ConverterConvert serum vitamin B12 between pg/mL, ng/L and pmol/L, and see why a normal result does not exclude deficiency.
- Vitamin B6 (PLP) Unit ConverterConvert plasma pyridoxal 5'-phosphate between µg/L, ng/mL and nmol/L — the active B6 vitamer, lowered by inflammation independently of B6 status, and raised into neurotoxicity by pyridoxine supplements.
- Vitamin C (Ascorbic Acid) Unit ConverterConvert plasma ascorbate between mg/dL, mg/L and µmol/L — 1.0 mg/dL is 56.8 µmol/L — and read the result knowing that a mishandled, unstabilised sample is the commonest cause of an apparent vitamin C deficiency.
- Vitamin D (25-OH) Unit ConverterConvert 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.
- Vitamin E IU to mg ConverterConvert vitamin E from international units to milligrams of alpha-tocopherol, using the correct factor for the natural or the synthetic form.
- Vitamin K1 (Phylloquinone) Unit ConverterConvert serum vitamin K1 between ng/mL, µg/L and nmol/L — and read the result alongside a lipid profile, because phylloquinone travels on triglyceride-rich lipoproteins and a raised triglyceride inflates it.
- Zinc to Copper Ratio CalculatorCalculate 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.
- Zinc Unit ConverterConvert plasma or serum zinc between µg/dL, µmol/L, µg/L and mg/L. The harder question is what the converted number is worth: the cut-off changes with sex, age, the time of day and whether the patient had eaten, the result falls in any inflammatory state, and a rubber stopper or a haemolysed sample destroys the measurement outright.