Haemoglobin (Hb)
Full Blood Count
▼
| Parameter | Normal Range |
|---|---|
| Male | 130-170 g/L |
| Female | 120-150 g/L |
| High (Polycythaemia) | Low (Anaemia) |
|---|---|
| Dehydration, COPD, polycythaemia vera, smoking | Iron deficiency, B12/folate deficiency, chronic disease, blood loss, haemolysis |
💡 Key: In men and post-menopausal women, iron deficiency anaemia = GI blood loss until proven otherwise. Investigate with OGD + colonoscopy.
White Cell Count (WCC)
Full Blood Count
▼
| Normal Range |
|---|
| 4.0-11.0 ×10⁹/L |
| High (Leucocytosis) | Low (Leucopenia) |
|---|---|
| Infection, inflammation, leukaemia, steroids, stress | Viral infection, chemotherapy, bone marrow failure, HIV, autoimmune |
Sodium (Na⁺)
U&Es / Electrolytes
▼
| Normal Range |
|---|
| 135-145 mmol/L |
| High (Hypernatraemia) | Low (Hyponatraemia) |
|---|---|
| Dehydration, diabetes insipidus, excess salt | SIADH, diuretics, heart failure, liver cirrhosis, Addisons, psychogenic polydipsia |
💡 Critical: Na⁺ <120 or >160 = urgent. Correct slowly to avoid central pontine myelinolysis (max 8-10 mmol/24h).
Potassium (K⁺)
U&Es / Electrolytes
▼
| Normal Range |
|---|
| 3.5-5.0 mmol/L |
| High (Hyperkalaemia) | Low (Hypokalaemia) |
|---|---|
| AKI, CKD, ACEi/ARBs, K-sparing diuretics, acidosis, rhabdomyolysis | Diuretics (loop/thiazide), vomiting, diarrhoea, alkalosis, insulin, salbutamol |
💡 Critical: K⁺ >6.5 = ECG changes (peaked T waves, wide QRS) = emergency. Treat: calcium gluconate, insulin+dextrose, salbutamol nebs.
Creatinine & eGFR
Renal Function
▼
| Parameter | Normal |
|---|---|
| Creatinine | 55-120 µmol/L |
| eGFR | >90 mL/min |
| CKD Stage | eGFR |
|---|---|
| Stage 1 | >90 (with kidney damage) |
| Stage 2 | 60-89 |
| Stage 3a | 45-59 |
| Stage 3b | 30-44 |
| Stage 4 | 15-29 |
| Stage 5 | <15 (dialysis) |
💡 AKI vs CKD: AKI = acute rise in creatinine. CKD = chronic low eGFR (>3 months). Check previous results to differentiate.
ALT (Alanine Aminotransferase)
Liver Function Tests
▼
| Normal Range |
|---|
| 7-56 U/L |
| Mildly Raised (1-3x) | Significantly Raised (>10x) |
|---|---|
| NAFLD, alcohol, drugs (statins, paracetamol), chronic hepatitis | Acute hepatitis (viral, drug), paracetamol overdose, ischaemic hepatitis |
💡 LFT pattern: Hepatocellular = ALT/AST raised. Cholestatic = ALP/GGT raised. Mixed = both raised.
TSH (Thyroid Stimulating Hormone)
Thyroid Function
▼
| Normal Range |
|---|
| 0.4-4.0 mU/L |
| High TSH | Low TSH |
|---|---|
| Hypothyroidism — Hashimotos, post-surgery, iodine deficiency | Hyperthyroidism — Graves, toxic nodule, thyroiditis |
💡 Remember: TSH is INVERSE to thyroid function. High TSH = underactive thyroid. Low TSH = overactive thyroid.
Troponin
Cardiac Markers
▼
| Normal Range |
|---|
| <14 ng/L (high-sensitivity assay) |
| Causes of Raised Troponin |
|---|
| MI (STEMI/NSTEMI), PE, myocarditis, heart failure, sepsis, renal failure, aortic dissection, tachyarrhythmia |
💡 Key: Troponin is sensitive but NOT specific for MI. Always interpret with clinical picture + ECG. Serial troponins (0h and 3h) help confirm.
CRP (C-Reactive Protein)
Inflammatory Marker
▼
| Normal Range |
|---|
| <5 mg/L |
| Mild (5-50) | Moderate (50-100) | Severe (>100) |
|---|---|---|
| Viral infection, mild inflammation | Bacterial infection, active inflammation | Severe sepsis, abscess, major surgery, burns |
INR (International Normalised Ratio)
Coagulation
▼
| Normal | Warfarin Target |
|---|---|
| 0.8-1.2 | AF/DVT/PE: 2.0-3.0 Mechanical valve: 2.5-3.5 |
| High INR Causes | Management |
|---|---|
| Warfarin excess, liver disease, DIC, vitamin K deficiency | INR 5-8: withhold warfarin. INR >8: vitamin K. Active bleeding: PCC + vitamin K |
HbA1c
Diabetes Monitoring
▼
| Category | HbA1c (mmol/mol) |
|---|---|
| Normal | <42 |
| Pre-diabetes | 42-47 |
| Diabetes | ≥48 |
| Well-controlled DM | <53 (target) |
💡 HbA1c reflects average blood glucose over 2-3 months. Unreliable in haemoglobinopathies, recent transfusion, or haemolytic anaemia.