Ketone body that cannot be detected by Rothera's test:
Rothera's test can only detect acetoacetate and acetone, and not beta-hydroxy butyrate. Rothera's test: Ketone bodies react with sodium nitroprusside (in the presence of NH3) to form a purple colored ring. Positive test indicate Acetoacetate and Acetone. No specific test available for beta-hydroxy butyrate. So, it is first oxidised to Acetoacetate, then Rothera's test is performed.
Beta oxidation of fatty acids
Acetoacetate
Acetone
Beta hydroxy butyrate
All the above can be detected
Beta hydroxy butyrate