These are the paediatric reference ranges used throughout the case decks and question sets on Pediatric Case Review. Every deck links here, and inside a deck the same tables open in a panel with the values quoted by that particular question highlighted.
They are typical values for teaching and exam preparation. Each laboratory quotes its own ranges, and several of these move with age — always read the local range printed on the report.
Typical paediatric values. Each laboratory quotes its own ranges, and several of these move with age.
| Measure | Reference | Note |
|---|
| Temperature | 36.5–37.5 °C | 38.0 or above is fever |
| Oxygen saturation | 94–100 percent in air | under 92 in air needs oxygen and admission |
| Capillary refill | 2 seconds or less | 3 seconds or more suggests shock |
| Heart rate | see the table above | age dependent |
| Respiratory rate | see the table above | age dependent |
| Blood pressure | see the table above for the hypotension floor | hypertension: systolic over roughly 105 mmHg at 1–2 y, 112 at 2–5 y, 118 at 5–12 y, 130 over 12 y |
| Ejection fraction | 55–70 percent | under 40 percent is systolic failure |
| Valve gradient (echo) | mean gradient under 25 mmHg is mild; 25–40 moderate; above 40 severe | for aortic stenosis – the peak instantaneous gradient reads higher than the mean, so check which one is quoted |
| Troponin | below the assay cut-off in a well child | a rise means myocardial injury, most often myocarditis in this age group |
| Measure | Reference | Note |
|---|
| FEV1 / FVC | FEV1 80 percent or more of predicted; ratio above 0.85 in children | asthma severity is graded on FEV1 off treatment: 80+ mild, 60–80 moderate, under 60 severe |
| Bronchodilator reversibility | a rise of 12 percent or more in FEV1 | this is what makes obstruction reversible, and it is the asthma test |
| Pleural fluid – exudate | protein above 30 g/L (3 g/dL), or fluid to serum protein above 0.5; LDH ratio above 0.6 | pH 7.2 or below, glucose under 2.2 mmol/L, or frank pus means it needs a drain |
| Dehydration | 5 percent mild, 10 percent moderate, 15 percent severe | estimated clinically – each 1 percent is 10 mL/kg of deficit |
| Measure | Reference | Age note |
|---|
| Haemoglobin | see age note | newborn (first 2 weeks) 14–22 g/dL; 1 month 10.7–17.1; physiological nadir 9.5–13.5 at 6–9 weeks; 6 months to 6 years 10.5–14; 6–12 years 11.5–15.5; over 12 years 12.0–16.0 |
| White cells | see age note | newborn (first week) 9–30 ×109/L; 2 weeks 5–21; 1 year 6–18; 4–10 years 4–13.5; adolescent 4.5–11 |
| Neutrophils | neutropenia under 1.5 ×109/L, severe under 0.5 | |
| Lymphocytes | see age note | the lymphocyte and neutrophil lines CROSS twice: lymphocytes predominate from about 1 week to 4 years, neutrophils either side of that |
| Eosinophils | under 0.5 ×109/L, or under 5 percent | |
| Platelets | 150–450 ×109/L | |
| MCV | lower limit roughly 70 + age in years (fL) | to about 12 years |
| ESR | under 10–20 mm/h | |
| CRP | under 5–10 mg/L | laboratory dependent |
| Measure | Reference | Note |
|---|
| Ferritin | newborn 25–200; 1 month 200–600; 2–5 months 50–200; 6 months to 15 years 7–140 µg/L (ng/mL) | a low value proves iron deficiency, but it is an acute phase protein, so a normal one during infection or inflammation does not exclude it |
| Serum iron / transferrin saturation | saturation under 16 percent suggests iron deficiency | iron is low in both iron deficiency and anaemia of chronic disease; the iron binding capacity is high in the first and low in the second |
| Reticulocyte count | first week of life 3–7; after that 0.5–1.5 percent | high means the marrow is responding, as in haemolysis or blood loss; low with anaemia means the marrow is the problem |
| Haematocrit | newborn 45–65, child 33–43 percent | above 65 percent in a newborn is polycythaemia |
| Prothrombin time / APTT | PT 11–14 s, APTT 25–38 s | an isolated long APTT with normal platelets suggests haemophilia; both prolonged suggests vitamin K deficiency, liver disease or consumption |
| Factor VIII / IX activity | 50–150 percent of normal | severe disease is under 1 percent, moderate 1–5, mild 5–40 |
| Von Willebrand factor antigen / activity | about 50–200 IU/dL | levels of 30–50 are common with blood group O; under 30 supports von Willebrand disease, and an activity-to-antigen ratio under about 0.7 suggests type 2 |
| Fibrinogen | 1.5–4.0 g/L | falls in consumption; it is also an acute phase protein, so a normal value during sepsis may already represent a fall |
| D-dimer | raised in consumption and in thrombosis | infection and inflammation raise it too, so a high value is not specific |
| Haemoglobin electrophoresis | HbA2 under 3.5 percent, HbF under 2 percent beyond infancy | HbA2 above 3.5 percent identifies beta thalassaemia trait; it is falsely lowered by coexisting iron deficiency |
| Haptoglobin / LDH | haptoglobin falls and LDH rises in haemolysis; LDH roughly under 300 U/L in a well child | read them beside the reticulocyte count and the bilirubin. LDH is also a bulk-of-disease marker in leukaemia and lymphoma and rises in tumour lysis |
| Direct antiglobulin test | negative in a healthy child | a positive test means antibody is bound to the red cells, which separates immune haemolysis from every other kind |
| Measure | Reference | Note |
|---|
| Sodium | 135–145 mmol/L | |
| Potassium | 3.5–5.0 mmol/L | up to 6.0 in the newborn |
| Chloride | 98–107 mmol/L | |
| Bicarbonate | 22–26 mmol/L | same value as on the gas |
| Urea | 2.5–6.5 mmol/L (7–18 mg/dL) | |
| Creatinine | infant 15–35, child 25–60, adolescent 50–90 µmol/L | rises with muscle mass, so an adult range over-reads a child; in the first week of life it reflects the mother’s level, up to about 90 µmol/L (Harriet Lane) |
| Glucose | 3.5–5.5 mmol/L (63–99 mg/dL) | newborn: above 2.6 mmol/L in the first 72 hours, above 3.3 mmol/L after 72 hours |
| Urine sodium / chloride | no fixed normal: urine sodium follows intake and is read with volume status; under 20 mmol/L means the loss is not renal | a high urine chloride points to the kidney or a diuretic |
| Urine and kidney | urine protein:creatinine ratio under 20 mg/mmol from 2 years, under 50 at 6 months to 2 years; albumin:creatinine ratio under 3 mg/mmol; calcium:creatinine ratio (mmol/mmol) 1–12 months under 2.2, 1–2 years under 1.5, 2–3 years under 1.4, 3–5 years under 1.1, 5–7 years under 0.8, over 7 years under 0.7; urine osmolality 50–1200 mOsm/kg and specific gravity 1.005–1.030, both set by hydration; eGFR over 90 mL/min/1.73 m2 from 2 years | GFR is low at birth and rises through infancy: mean 41 ± 15 at 1 week, 66 ± 25 at 2–8 weeks, 96 ± 22 from 8 weeks to 2 years (mL/min/1.73 m2). Spot-urine ratios are read against age; urine sodium has no fixed normal (row above) |
| Measure | Reference | Note |
|---|
| ALT / AST | 10–40 / 10–45 U/L | |
| GGT | 5–35 U/L | up to 200 in the first months of life |
| Alkaline phosphatase | child 100–400 U/L, higher in the growth spurt | an adult range makes normal childhood bone turnover look like disease |
| Bilirubin (total) | under 17 µmol/L (1 mg/dL) beyond the newborn period | in the newborn, read against the hour-specific treatment chart |
| Conjugated bilirubin | under 5 µmol/L (0.3 mg/dL) | cholestasis: over 17 µmol/L (1.0 mg/dL) is abnormal at any age, whatever the total (NASPGHAN–ESPGHAN 2017); the older rule of over 20 percent of the total is no longer used |
| Albumin | 35–50 g/L | term newborn 25–50 g/L |
| Cholesterol / triglycerides | total cholesterol under 4.4 mmol/L, triglycerides under 1.5 mmol/L | both rise steeply in nephrotic syndrome, in proportion to the albumin loss |
| Total protein | 60–80 g/L | albumin plus globulin – a low total with a low albumin points to loss rather than to synthesis; newborn 46–70 g/L (Harriet Lane) |
| INR / prothrombin time | INR 0.8–1.2 | the earliest measure of failing liver synthesis, and it does not correct with vitamin K once the liver is the problem |
| Creatine kinase | under 200 U/L | thousands mean muscle: a Duchenne CK runs 10 000 to 20 000 from infancy |
| Ammonia | newborn under 110, child under 50 µmol/L | |
| Calcium / magnesium / phosphate | 2.2–2.7 / 0.7–1.0 / 1.03–1.87 mmol/L (child) | phosphate by age: 0–9 days 1.45–2.91, 10 days–2 years 1.29–2.10, 3–9 years 1.03–1.87, 10–15 years 1.07–1.74, over 15 years 0.78–1.42; calcium in the first week of life 1.9–2.8 (Harriet Lane, 21st ed.). Ranges depend on the laboratory and its assay |
| Lipase or amylase | lipase: under 1 year 5–50, 1 year and over 10–60 U/L; amylase: under 1 year 5–65, 1 year and over 30–110 U/L | three times the upper limit defines pancreatitis; ranges are laboratory dependent |
| Sweat chloride | under 30 normal, 30–59 intermediate, 60 or more diagnostic | |
| Caeruloplasmin | 0.2–0.6 g/L | low in Wilson disease, and it is an acute phase protein, so a normal level during inflammation does not exclude it |
| Parathyroid hormone | 1.6–7.5 pmol/L | rises early in chronic kidney disease, before calcium or phosphate move |
| Antistreptolysin O titre | under 5 years 70 or less; from 5 years under 320 IU/mL | the upper limit depends on age, assay and local exposure (school-age studies give 240–360). Peaks 3–6 weeks after a streptococcal throat infection; a single raised value shows exposure, not active disease |
| Malaria parasitaemia | any level is abnormal | above 2 percent counts as severe in a non-immune child, and above 10 percent is an indication for exchange transfusion in some protocols |
| Measure | Reference | Note |
|---|
| Thyroid stimulating hormone | 0.5–5.0 mIU/L beyond the newborn period | it surges to 20 or more in the first days of life, so a newborn screen is read against its own threshold and not against this range |
| Free T4 | 12–22 pmol/L | a low free T4 with a high TSH is primary hypothyroidism; a low free T4 with a low or normal TSH points to the pituitary |
| Cortisol | morning 140–500 nmol/L | the value only means something beside the time and the clinical state: under 100 during hypoglycaemia or shock is inappropriately low |
| ACTH | 2–11 pmol/L (10–50 ng/L) | high with a low cortisol is adrenal failure; high with a high cortisol points above the adrenal |
| 17-hydroxyprogesterone | under 10 nmol/L after the first few days | grossly raised in 21-hydroxylase deficiency, and the newborn screening analyte for congenital adrenal hyperplasia |
| Growth hormone / IGF-1 | a random growth hormone is uninterpretable; peak over 7 µg/L on provocation is normal | IGF-1 is read against age and pubertal stage, and is low in malnutrition as well as in deficiency |
| LH / FSH | prepubertal under 0.3 IU/L | an LH above 0.3 with a pubertal response to stimulation means the axis has switched on, which is what separates central from peripheral puberty |
| Testosterone / oestradiol | prepubertal testosterone under 0.5 nmol/L, oestradiol under 20 pmol/L | |
| HbA1c | under 42 mmol/mol (6.0 percent) | 48 mmol/mol (6.5 percent) or more is diagnostic of diabetes; it is unreliable when red cell survival is shortened |
| Insulin / C-peptide | should be undetectable when glucose is low | any measurable insulin during a hypoglycaemic episode is abnormal and is the whole diagnosis in hyperinsulinism |
| Ketones (blood) | under 0.6 mmol/L | 3.0 or more with acidosis defines ketoacidosis; absent ketones during hypoglycaemia is the abnormal finding, not a reassuring one |
| 25-hydroxyvitamin D | sufficient above 50, deficient below 25 nmol/L | this is the storage form and the one to measure; the active 1,25 form can be normal or high in nutritional rickets |
| Plasma metanephrines | any clear elevation is abnormal | the screening test for a catecholamine-secreting tumour; caffeine and several drugs raise it falsely |
| Renin / aldosterone | both read against sodium intake and posture | renin rises in salt-losing states and is suppressed when mineralocorticoid excess is driving the blood pressure |
| Measure | Reference | Note |
|---|
| Anion gap | 8–16 mmol/L | sodium minus chloride and bicarbonate. Above 16 means an unmeasured acid: lactate, ketones, an organic acid or a toxin |
| Toxicology | paracetamol, salicylate and ethanol: undetectable; serum iron: newborn 17.9–44.8, infant 7.2–17.9, child 9.0–21.5, over 12 years 9.0–31.3 µmol/L; carboxyhaemoglobin under 2 percent; methaemoglobin under 1.5 percent; serum osmolality 275–295 mOsm/kg (newborn 266–295); osmolal gap under 10 mOsm/kg; digoxin (therapeutic) 0.8–2.0 µg/L; blood lead under 3.5 µg/dL; plasma cholinesterase: laboratory dependent | a paracetamol level is read against the treatment line, not against a normal range; the digoxin figure is a therapeutic range and the lead figure a population reference value (CDC 2021). Anion gap and creatine kinase have their own rows |
| Uric acid | 0–14 days 0.16–0.75; 15 days to 1 year 0.09–0.37; 1–11 years 0.10–0.28; 12–18 years 0.15–0.45 mmol/L (girls up to 0.34) | high in tumour lysis, renal failure and several inborn errors; low in molybdenum cofactor deficiency. 1 mg/dL = 0.0595 mmol/L (CALIPER) |
| Plasma phenylalanine | under 120 µmol/L | the newborn screening analyte; treatment is started above about 360 µmol/L and the level guides dietary control |
| Plasma amino acids / urine organic acids | qualitative | the PATTERN names the disorder rather than any single value, and the sample must be taken during the acute illness to be interpretable |
| Measure | Reference | Note |
|---|
| Total IgA | see age note | 1–3 years 0.2–1.0, 4–6 years 0.3–1.3, school age 0.5–2.0, adult 0.8–3.0 g/L. Selective IgA deficiency is under 0.07 g/L |
| IgG / IgM | IgG 5–16 g/L, IgM 0.5–2.0 g/L beyond infancy | IgG falls to a physiological trough at 3–6 months as maternal antibody clears |
| Tissue transglutaminase IgA | negative under 7 U/mL; 10x the upper limit supports coeliac disease | it is an IgA antibody, so it reads falsely negative when total IgA is low – always check the total IgA beside it |
| C3 / C4 | C3 0.75–1.65 g/L, C4 0.14–0.54 g/L | a low C3 that recovers by 8–12 weeks is post-infectious nephritis; one that stays low beyond that points to C3 glomerulopathy or membranoproliferative disease, and a low C4 alongside it suggests lupus |