CBC - Although it is a non-specific finding, a leukocytosis is typically seen.
Chemistry Panel - Lactic acidosis is a common finding and is seen earlier in the disease course in diabetic patients. Renal insufficiency is also commonly seen as well.
Urinalysis - Will often show evidence of pyelonephritis, however if the<unk>  is secondary to hematogenous spread, the urine could be sterile. Therefore a negative U/A does NOT rule out a<unk> .
Blood and urine cultures
CT
Imaging modality of choice
Sensitivity ~90%.
Renal ultrasound - A fluid filled mass extending from the renal cortex into the<unk>  fat can be seen.
Imaging modality of choice
Sensitivity ~90%.
Perinephric abscess
Genitourinary infection
Renal abscess
Acute cystitis 
Psoas abscess
Pyelonephritis
Traumatic epididymitis
Urethritis