Table 2.

Diagnostic work-up of patients with AKI.

Investigations	Comments
Essential tests
Urinalysis	Proteinuria and/or haematuria represent an active urinary sediment suggestive of glomerular disease
Serum creatinine, urea and electrolytes
Full blood count and blood film	To rule out thrombotic mircoangiopathy and haemolysis; eosinophilia may be present with interstitial nephritis
C-reactive protein	elevated in inflammatory diseases and/or infections
Arterial or venous bicarbonate
Investigations to be considered depending on history and/or clinical signs
Creatine kinase	To rule out rhabdomyolysis
Serum and urine protein electrophoresis	To rule out myeloma
Antinuclear antibody (ANA)	In case of possible diagnosis of SLE or connective tissue disease
Antineutrophil antibody (ANCA)	In case of possible systemic vasculitis
Anti-streptolysin O titres	To rule out post streptococcal glomerulonephritis
Anti-glomerular basement membrane antibody	To rule out Goodpasture's disease
Complement levels	Reduced in SLE, infectious endocarditis and cryoglobulinaemia
Hep B, Hep C and HIV serology	To rule out renal disease caused by viral infections
Renal ultrasound	To assess renal size; to rule out obstruction and chronic kidney damage