BLOOD TESTS
Test	Application
Biochemistry
Potassium	• Renal failure • Deciding on suxamethonium • Diagnosis of cardiac arrhythmias • Fluid therapy
Sodium	•Fluid therapy
Glucose	•Diabetic control
Creatinine or urea	•Renal function
Haematology
Haemoglobin concentration	•Anaemia
White cell count	•High in the presence of infection •Low in advanced HIV
Platelets	•Bleeding tendency
Blood film	•Malaria parasites1
1 Important in fever, especially postoperatively, as the stress of surgery may provoke a bout of malaria