A child presents with complaints of oliguria, abdominal distension and diarrhoea. On examination, there is deep jaundice. Hepatomegaly was present measuring 4 cm below the costal margin. Conjugated bilirubin of the following tests is of least importance toin blood was 38 mg/dL, and there was urine urobilinogen and bile pigments. Hemoglobin was 4mg/dL, and serum creatinine was 3mg/dL. Which diagnose this case -
Serum ceruloplasmin measurement is useful in the diagnosis of Wilson's disease, but Wilson's disease in the above patient can easily be ruled out because in Wilson's disease there is no renal involvement, whereas the patient in question is having renal involvement (Serum Creatinine 3 mg/dL).
Leptospiral antibody level

Leptospiral antibody measurement is useful in the diagnosis of leptospirosis.
The symptomatic profile of the patient is very similar to that of severe leptospirosis (Weil's syndrome).

C/F of Well's syndrome 

Jaundice               
Hemolysis             
Renal failure (During 2nd wk).
Hemorrhagic diathesis
Hepatomegaly 
Rhabdomyolysis
Spleenomegaly  
Congestive heart failure  
Pulmonary involvement


G-6PD level -

During G-6 PD deficiency hemolysis occurs which can give rise to unconjugated bilirubinemia.
The patient is giving evidence of unconjugated hyperbilirubinemia. So G-6PD level can be checked to find out the cause of unconjugated hyperbilirubinemia.

Reticulocyte count - 

The reticulocyte count is done to check whether the patient is suffering from any hemolytic anaemia (which can be a cause of unconjugated bilirubinemia).
G–6–PD level in blood
Serum ceruloplasmin
Reticulocyte count
Leptospiral antibody level