<prompt> Answer this question truthfullyWhen diagnosing obstructive jaundice secondary to inflammation from choledocholithiasischolangitis, which diagnostic method is considered necessary?  <response>: <reason> The diagnostic method considered necessary for obstructive jaundice secondary to inflammation from choledocholithiasischolangitis is a right upper quadrant ultrasound RUQ US with magnetic resonance cholangiopancreatography MRCP or endoscopic retrograde cholangiopancreatography ERCP. 