Chemistry & Electrolytes
Every chemistry & electrolytes 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.
29 calculators in this section
- Adrogué-Madias Formula CalculatorPredict the change in serum sodium from one litre of a chosen infusate, using the Adrogué-Madias formula.
- Albumin Unit ConverterConvert albumin between g/dL, g/L and µmol/L, and see why a low albumin marks the severity of illness rather than nutritional state.
- Aldolase Unit ConverterConvert serum aldolase between U/L, IU/L, µkat/L and nkat/L. Aldolase is a muscle enzyme read alongside creatine kinase in suspected inflammatory myopathy, and its reference interval belongs to a named method — two large laboratories publish adult limits that do not overlap.
- Amylase Unit ConverterConvert serum amylase between U/L, IU/L, µkat/L and nkat/L, and see why a normal amylase does not exclude pancreatitis and a very high one does not mean a severe attack.
- Bicarbonate Unit ConverterConvert bicarbonate between mmol/L, mEq/L and mg/dL. Bicarbonate is monovalent, so mmol/L and mEq/L are the same number — the harder question is which bicarbonate your report means.
- Calcium-Phosphate Product CalculatorCalculate the calcium-phosphate product, a legacy marker of vascular calcification risk in chronic kidney disease.
- Calculated Serum Osmolality CalculatorCalculate serum osmolality from sodium, glucose, BUN and ethanol to compare against the measured value and detect an osmolal gap.
- Ceruloplasmin Unit ConverterConvert ceruloplasmin between mg/dL, g/L, mg/L and µmol/L, and see why a normal level does not exclude Wilson disease.
- Chloride Unit ConverterConvert chloride between mmol/L, mEq/L and mg/dL. Chloride is monovalent, so mmol/L and mEq/L are the same number — and the result only means something once it is read against sodium.
- Cholinesterase Unit ConverterConvert plasma (pseudo)cholinesterase between U/L, IU/L, µkat/L and nkat/L, and keep it separate from the red-cell acetylcholinesterase used in organophosphate poisoning.
- Creatine Kinase (CK) Unit ConverterConvert creatine kinase between U/L, IU/L, µkat/L and nkat/L, with the statin and rhabdomyolysis thresholds and why one reference interval does not fit everyone.
- Free Water Deficit CalculatorCalculate the free water deficit in hypernatraemia from body weight, measured sodium and total body water fraction.
- Globulin and A:G Ratio CalculatorCalculate globulin as total protein minus albumin, with the A:G ratio and what a reversed ratio actually tells you about the two components.
- Hyperkalaemia (High Potassium) Interpreter: Real or Spurious?Decide whether a high potassium is real before deciding how urgent it is. The page checks the sample first — haemolysis, EDTA contamination, high platelets or white cells, a delayed or chilled sample, fist clenching — then grades a real result by the 2023 UK Kidney Association guideline, shows where the KDIGO 2020 grading differs, and says what the ECG changes about urgency.
- Hypernatraemia (High Sodium) Cause InterpreterFind the cause of a high sodium from the urine. Enter the urine osmolality and the 24-hour urine volume, and the response to desmopressin if it was given. The page separates water lost outside the kidney or never drunk, an osmotic diuresis (with the osmolar excretion worked out), and diabetes insipidus — now called AVP deficiency and AVP resistance under the 2022 renaming.
- Hypomagnesaemia (Low Magnesium) InterpreterGrade a low magnesium, then use the fractional excretion of magnesium (FEMg) to decide whether it is being lost through the kidney or the gut, and check the drug history against that answer — PPIs, diuretics, alcohol, calcineurin inhibitors, cisplatin — and Gitelman syndrome. It also explains why a low magnesium keeps a low potassium or calcium from correcting.
- Hyponatraemia (Low Sodium) Diagnostic InterpreterWork out why a sodium is low. Follow the 2014 European hyponatraemia guideline step by step: correct for glucose, rule out pseudohyponatraemia and hypertonic causes, then read the urine osmolality, the urine sodium and diuretic use, and only then the volume state. The page gives the likely cause — SIAD, low effective volume, oedema, diuretics, adrenal or thyroid, primary polydipsia or low solute intake — the biochemical severity, and what symptoms change.
- Hypophosphataemia & Refeeding Syndrome Risk InterpreterGrade a low phosphate, then apply the NICE CG32 refeeding-risk criteria exactly as published — one of four major criteria, or two of four minor ones — and see how the 2020 ASPEN consensus criteria differ. Add the TmP/GFR result to decide whether phosphate is being lost through the kidney or has moved into cells.
- Lactate Dehydrogenase (LDH) Unit ConverterConvert LDH between U/L, IU/L, µkat/L and nkat/L — and start with the fact that haemolysing the sample raises the result all by itself.
- Lipase Unit ConverterConvert serum lipase between U/L, IU/L, µkat/L and nkat/L, with the three-times-upper-limit diagnostic threshold and why the height of the rise says nothing about severity.
- Magnesium Unit ConverterMagnesium is divalent: mEq/L is exactly twice mmol/L, and mg/dL is a different scale again. Convert between all three without making the twofold error.
- Potassium Unit ConverterConvert potassium between mmol/L, mEq/L and mg/dL. Potassium is monovalent, so mmol/L and mEq/L are the same number — the real risk on this test is the sample, not the arithmetic.
- Rhabdomyolysis CK Interpreter: How High Is Too High?Interpret a raised creatine kinase (CK) when rhabdomyolysis is the question. Enter the CK and your laboratory's upper limit, the cause, the kidney function and the timing; the page gives the multiple of the upper limit against the five-times definition most studies use, explains why the CK alone does not predict kidney failure, and shows how much the cause matters, from the 2013 McMahon cohort of 2371 patients.
- Serum Urate Target in Gout: Below 6 or 5 mg/dL? InterpreterCheck a serum urate (uric acid) against the treat-to-target goals for gout: below 6 mg/dL (360 µmol/L) in the ACR 2020 and EULAR 2016 guidelines, and below 5 mg/dL (300 µmol/L) for severe or tophaceous gout in EULAR's. Enter the result in mg/dL, µmol/L or mmol/L; the page gives the value in both units, where it sits against each target and the saturation point, and why a normal urate during a flare does not exclude gout.
- Sodium Correction for HyperglycaemiaCorrect measured sodium for the diluting effect of hyperglycaemia, using either the Katz or Hillier factor.
- Sodium Deficit CalculatorCalculate the sodium deficit in hyponatraemia between a measured and target sodium, with correction rate limits.
- Sodium Unit ConverterConvert sodium between mmol/L, mEq/L and mg/dL. Sodium is monovalent, so mmol/L and mEq/L are the same number — and the mg/dL column is the one that needs care.
- Total Protein Unit ConverterConvert serum total protein between g/dL, g/L and mg/dL — and use it the way it is meant to be used, subtracted from albumin to give the globulin and the A:G ratio.
- Uric Acid (Urate) Unit ConverterConvert urate between mg/dL, µmol/L and mmol/L — and keep two different numbers apart: the sex-specific reference interval, and the 360 µmol/L treat-to-target used in gout.