UA/Urine cultures
Chemistry
CBC (if suspect infection or massive hematuria)
Bedside ultrasound (to verify<unk> 
Incomplete<unk>  is PVR > 50ml and > 100ml in patients > 65 years of age
Post-void residual of 150-200 cc is particularly concerning
Incomplete<unk>  is PVR > 50ml and > 100ml in patients > 65 years of age
Post-void residual of 150-200 cc is particularly concerning
Acute urinary retention
Obstructive causes
Acute cystitis
BPH
Diabetes insipidus
Prostate cancer
TURP syndrome
Blood clot