Haematology — Red Cell & Indices
Every haematology — red cell & indices 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.
24 calculators in this section
- Absolute Reticulocyte Count CalculatorConvert a reticulocyte percentage into an absolute count in ×10⁹/L — the number that tells you whether the marrow is actually responding.
- Anaemia Severity Classifier (WHO 2024)Grade a haemoglobin against the revised WHO 2024 cutoffs — in g/L and g/dL, with the altitude and smoking adjustments applied, and with the 2011 values beside them so you can see that exactly two things changed.
- Anaemia Type Classifier (MCV-Based)Classify an anaemia from the MCV and then narrow it with the RDW, the reticulocyte count and the iron studies — starting from the reason the MCV misleads, which is that a mean cannot see two populations of cells.
- Corrected Reticulocyte Count CalculatorCorrect the reticulocyte percentage for anaemia by scaling it to a reference haematocrit of 45%, so the marrow response can be judged fairly.
- England & Fraser Index CalculatorThe original 1973 discriminant function for microcytic anaemia: a negative result favours thalassaemia trait, a positive one iron deficiency. It prioritises who is tested — it does not diagnose either.
- Green & King Index CalculatorPrioritise a microcytic anaemia toward thalassaemia trait or iron deficiency using MCV, RDW and haemoglobin. A screening aid for deciding who gets electrophoresis — never a diagnosis.
- Haematocrit from Haemoglobin CalculatorEstimate the haematocrit as three times the haemoglobin — the rule of three — and see the anaemias in which that approximation stops holding.
- Haematocrit Unit ConverterConvert haematocrit between % and L/L — 45% is 0.45 L/L — and read it as what it is: a concentration that most analysers calculate rather than measure, and that fluid moves without a red cell being gained or lost.
- Haemoglobin Unit ConverterConvert haemoglobin between g/dL, g/L and mmol/L — using the globin monomer mass, which is why SI reports read 8 to 11 mmol/L rather than 2 to 3.
- Haemolysis Screen Interpreter — LDH, Haptoglobin, Retics, DATEnter the haemolysis screen — LDH, haptoglobin, reticulocytes, unconjugated bilirubin and the direct antiglobulin test — with the film, urine, inflammation, recent transfusion and whether the sample itself was haemolysed. It says whether haemolysis is likely, then immune or non-immune and intravascular or extravascular, and it catches the two classic traps: a haemolysed sample, and a haptoglobin held up by inflammation.
- Macrocytosis Interpreter — High MCV: B12, Folate, Drugs or MDS?Enter the MCV with what is known — B12 and folate against the NICE 2024 and BSH lines, reticulocytes, alcohol, liver disease, thyroid, drugs such as methotrexate, hydroxycarbamide, azathioprine and antiretrovirals, and whether other counts are low. It separates megaloblastic from non-megaloblastic causes, handles the indeterminate B12 with active B12 and methylmalonic acid, and says when a film and a marrow are needed for myelodysplasia.
- MCH Calculator (Mean Corpuscular Haemoglobin)Calculate mean corpuscular haemoglobin from haemoglobin and red cell count, and see why it usually tracks MCV rather than adding new information.
- MCHC Calculator (Mean Corpuscular Haemoglobin Concentration)Calculate MCHC from haemoglobin and haematocrit, and learn why a genuinely high result is rare enough to demand a blood film first.
- MCV Calculator (Mean Corpuscular Volume)Calculate mean corpuscular volume from haematocrit and red cell count, and read the microcytic-normocytic-macrocytic split correctly.
- Mean Platelet Volume (MPV) InterpreterRead the mean platelet volume together with the platelet count, because neither means much alone: a low count with large platelets points to destruction, a low count with small platelets to a production failure.
- Mentzer Index CalculatorScreen a microcytic anaemia toward thalassaemia trait or iron deficiency using MCV and red cell count, before confirming with ferritin or haemoglobin electrophoresis.
- Platelet Count Unit ConverterConvert a platelet count between ×10⁹/L, ×10³/µL, K/µL and cells per microlitre — and check EDTA-dependent pseudothrombocytopenia before acting on an unexpectedly low one.
- Plateletcrit (PCT) CalculatorCalculate the plateletcrit — the fraction of blood volume occupied by platelets — from the platelet count and the mean platelet volume, and see why a normal result can hide an abnormal count.
- Polycythaemia Interpreter — High Haemoglobin or HaematocritEnter a haemoglobin or haematocrit, the patient's sex and what is known — whether it has been repeated, JAK2, serum erythropoietin, smoking, hypoxia, testosterone, SGLT2 inhibitors, dehydration. It reads the value against the WHO and ICC 2022 polycythaemia vera thresholds and the British Society for Haematology's, which differ for men, and separates polycythaemia vera from secondary and relative erythrocytosis.
- RDW-CV to RDW-SD CalculatorEstimate RDW-SD in femtolitres from the RDW-CV your analyser printed and the MCV — with the Gaussian coefficient most versions of this conversion leave out, and an honest account of where the estimate fails.
- Red Blood Cell Count Unit ConverterConvert a red cell count between ×10¹²/L, ×10⁶/µL, cells/µL and cells/mm³ — the first two are the same number — and see why the count itself carries so little of the information.
- Red Cell Indices InterpreterClassify an anaemia from the MCV, MCHC and RDW, and see the differential each pattern opens up — and where the pattern stops and the confirmatory test has to start.
- Reticulocyte Production Index (RPI) CalculatorCalculate the RPI by correcting the reticulocyte count for both anaemia and the longer circulating lifespan of prematurely released reticulocytes.
- Thrombocytosis Interpreter — High Platelet Count, Reactive or ET?Enter a platelet count with the context — an obvious reactive cause, whether it has persisted, driver-mutation results and age. It separates reactive thrombocytosis, which is most of them, from the clonal kind, flags the counts at which bleeding rather than clotting becomes the risk, and says when a high platelet count is a reason to look for cancer.