CBC
Infection may cause leukocytosis or leukopenia
LFTs
Elevated in biliary, vascular, and rejection<unk> 
BMP
Hyperglycemia, sodium, and potassium derangements not uncommon
Coags
Tacrolimus/cyclosporine levels
Infection may cause leukocytosis or leukopenia
Elevated in biliary, vascular, and rejection<unk> 
Hyperglycemia, sodium, and potassium derangements not uncommon
Additional work up will depend on presentation, but may include:
Infectious workup
Blood and urine cultures
+/- PCR and other studies for viral/fungal pathogens as indicated
Diagnostic paracentesis if evidence of SBP
Abdominal CT or ultrasound with doppler, if concern for rejection, biliary obstruction, or thrombosis
Biliary<unk>  may need ERCP
Blood and urine cultures
+/- PCR and other studies for viral/fungal pathogens as indicated
Diagnostic paracentesis if evidence of SBP
Liver transplant complications
Most common problems in liver transplant patients involve:
Pancreas transplant complications
Acute graft rejection
Kidney transplant complications
1 in 5 have rejection during first year, usually within <1 mo
Ischemic hepatitis
Vascular thrombosis