This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pleural Effusion & Pneumothorax, Subject name: Medicine
Water test is done for? 
Select and explain. 
A. Pneumothorax, B. Diabetic insipidus, C. Peritonitis, D. Bladder injury
A: Pneumothorax
Answer: A: Pneumothorax 
Explanation: Ans. (a) PneumothoraxA very surprising question included in medicine as nothing is mentioned about this test in most books.In cases of spontaneous pneumothorax air leaks into the pleural cavity. This air may be reabsorbed but leaves behind a bronchopleural fistula which on autopsy can be picked by "water test".This is not a clinical test but done by forensic team post mortem.Please don't confuse with:* Water loading test is done for SIADH* Water deprivation test is done for diabetes insipidus.