A destitute woman is admitted to the hospital with altered sensorium and dehydration; urine analysis shows mild proteinuria and no sugar; what other test would be desirable
Rothera

The women are presenting with altered sensorium and dehydration, which may be the presenting features of ketoacidosis. She has already been tested for urine sugar (rules out diabetic ketoacidosis) and protein.
The important investigation missed out in this patient is ketone bodies in urine, which is important to reach the diagnosis of starvation ketosis. Ketone bodies are tested by Rothera's test.
About other options
Fouchet
Rothera
Hays
Benedicts