Neonatal & Paediatric Laboratory
Every neonatal & paediatric laboratory 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
- Bilirubin to Albumin (B:A) Ratio CalculatorThe bilirubin to albumin ratio in conventional units, against the AAP thresholds for exchange transfusion — an adjunct to the total bilirubin, never a replacement for it, and a test NICE explicitly advises against using.
- CKiD U25 eGFR CalculatorThe CKiD U25 creatinine equation for children and young adults up to 25 years, with the age- and sex-specific k coefficient that the bedside Schwartz equation lacks — built to work across the paediatric-to-adult transition, where Schwartz and CKD-EPI disagree.
- Cord Blood Gas InterpreterPaired umbilical arterial and venous results read together: whether the pair is genuinely arterial and venous at all, and whether the arterial sample meets the conventional definition of significant metabolic acidaemia.
- Neonatal Bilirubin Rate of Rise CalculatorHow fast a newborn's bilirubin is climbing, from two measurements and the hours between them — against NICE's figure for a bilirubin rising rapidly and the AAP 2022 rates that suggest haemolysis. The rate matters independently of the level.
- Neonatal CSF Reference Interval InterpreterNeonatal CSF white cell count, protein and CSF:blood glucose ratio read against age-banded reference intervals — because the adult upper limits would call almost every healthy newborn abnormal, and the published neonatal limits do not agree with each other.
- Neonatal Direct Antiglobulin Test InterpreterThe newborn direct antiglobulin test read with the maternal and infant blood group and the antibody identified — because a positive DAT does not by itself mean haemolysis, and a negative one does not exclude ABO haemolytic disease.
- Neonatal Early-Onset Sepsis Risk CalculatorThe Kaiser Permanente early-onset sepsis calculator turns gestational age, the highest maternal intrapartum temperature, the duration of rupture of membranes, maternal GBS status and intrapartum antibiotics into a risk per 1,000 births, then multiplies it by the infant's clinical examination. This page does not reproduce that arithmetic and does not try to. Run the official Kaiser Permanente neonatal early-onset sepsis calculator, then bring the number it gives you back here: what follows is the management band that number falls in, what the examination step actually did to it, and where the published misses are concentrated.
- Neonatal Exchange Transfusion Threshold CalculatorWhere a measured serum bilirubin sits relative to the NICE CG98 exchange transfusion line, for a baby born at 38 weeks or more. Reaching this line is an emergency, not a calculation — it means continuous intensified phototherapy now and a call to the neonatal team.
- Neonatal Glucose Infusion Rate CalculatorGlucose infusion rate in mg/kg/min from the dextrose concentration, the infusion rate and the baby's weight — the number neonatal teams titrate against, and the one that flags hyperinsulinism when it climbs.
- Neonatal Hyperammonaemia InterpreterA raised ammonia in a newborn is a metabolic emergency in which the time to treatment predicts the outcome — and it is also, most of the time, a squeezed heel-prick. Three things this page does that a general ammonia page cannot. The neonatal reference interval is much higher than the adult one, so the adult upper limit over-calls. The sampling artefacts are the commonest cause of a raised result and are recognisable. And the differential splits cleanly on the blood gas and the ketones: respiratory alkalosis with a normal anion gap points at a urea cycle defect, a raised anion gap acidosis with ketones at an organic acidaemia.
- Neonatal Hypoglycaemia Threshold InterpreterNewborn blood glucose read against the BAPM operational thresholds, which are lower than adult thresholds and depend on whether the baby has abnormal clinical signs — and on whether the number came from a laboratory or from a cot-side glucometer.
- Neonatal Partial Exchange Transfusion for Polycythaemia CalculatorThe volume to exchange with normal saline in a symptomatic polycythaemic newborn, from weight, the observed haematocrit and the target. The procedure is for symptomatic babies: the evidence in asymptomatic polycythaemia does not support it.
- Neonatal Phototherapy Threshold CalculatorWhere a measured serum bilirubin sits relative to the NICE CG98 phototherapy line, for a baby born at 38 weeks of gestation or more, by postnatal age in hours. Babies born before 38 weeks have lower thresholds that this page does not carry.
- Neonatal Thrombocytopenia InterpreterA low platelet count in a newborn is read by when it appeared at least as much as by how low it is. Under 72 hours of age it usually points at the pregnancy — placental insufficiency, growth restriction, pre-eclampsia, perinatal asphyxia. After 72 hours it usually points at sepsis or necrotising enterocolitis. And a severe, isolated thrombocytopenia in an otherwise well term infant is the one pattern that is neither, and the one that needs a specific treatment urgently. The transfusion threshold is lower than most people expect, and there is a randomised trial behind that.
- Neonatal Thyroid Screening TSH InterpreterNewborn blood spot TSH read against the cut-offs of the programme that produced it — with the unit trap that matters most: a blood spot TSH is a whole-blood concentration and is about two thirds of the serum TSH it is so often compared with.
- Newborn Weight Loss Percentage CalculatorPercentage weight loss from birth weight, read against the action points that are actually published — and against age in hours, because the hour-specific nomograms separate normal from excessive before the first day is out.
- Paediatric Blood Pressure Percentile InterpreterHypertension in a child is defined by percentile against age, sex and height, not by an absolute number — which is exactly why it gets missed. This page does two things. For any age it applies the absolute limbs of the 2017 AAP definitions, which are exact because the guideline says "whichever is lower": 120 systolic is at least elevated, 130/80 is at least stage 1 and 140/90 is stage 2, in a four-year-old as much as in a fourteen-year-old. Below those, for ages 1 to 12, it applies the guideline's own simplified screening table. It does not reproduce the full age-sex-height percentile tables and does not reconstruct them — a reading that reaches the screen is sent to the real table, not diagnosed here.
- Paediatric Corrected Age CalculatorCorrected age from chronological age and gestational age at birth — the age a preterm baby must be assessed against for growth, development and many reference intervals, because chronological age makes a normal preterm baby look abnormal.
- Paediatric Creatinine Reference Interval InterpreterSerum creatinine read against age- and sex-specific reference intervals from an enzymatic, IDMS-anchored dataset — because an adult interval is badly wrong in a child, and a creatinine inside the child's own interval can still sit on a substantially reduced GFR.
- Paediatric Dehydration Fluid Deficit CalculatorFluid deficit in millilitres from percentage dehydration and weight, with the replacement schedules that are actually published — and the finding that clinical estimation of percentage dehydration is unreliable, which is the input this arithmetic depends on.
- Paediatric DKA Severity InterpreterDiabetic ketoacidosis in a child is graded by venous pH and bicarbonate, and the grade is only the first half of the reading. Effective osmolality and corrected sodium tell you whether this is ordinary DKA, a hyperosmolar state, or both at once — and the features associated with cerebral injury tell you what to watch, which is not the same as telling you to slow the fluids. This page grades and interprets. It is not a fluid protocol: the paediatric maintenance fluid calculator and the paediatric dehydration fluid deficit calculator are the pages for that.
- Paediatric Iron Deficiency InterpreterFerritin is the best single test for iron deficiency in a child and it is also an acute-phase reactant, so a normal ferritin with a raised CRP does not exclude deficiency — it means the test has been neutralised. This page reads ferritin and transferrin saturation against the age-banded decision thresholds three bodies publish, which disagree: the WHO uses 12 and 15 µg/L, the AAP and ASH use 20 and 30 ng/mL. All three are printed. What is not printed is an age-banded paediatric ferritin reference interval, because no such thing is soundly published — for that, ask your own laboratory.
- Paediatric Maintenance Fluid CalculatorRoutine maintenance intravenous fluid volume in a child by the Holliday-Segar method, in the form NICE NG29 states it — with the hourly 4-2-1 equivalent, and the reason maintenance fluid in children is now isotonic rather than hypotonic.
- Paediatric Maximum Blood Draw Volume CalculatorHow much blood may safely be taken from a child, from weight and estimated blood volume, against the published percentage limits — with the source of each percentage named, because they differ.