This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Forensic Medicine
All are tests for detecting carbon monoxide in blood except? 
Select and explain. 
A. Kastle mayer test, B. Tannic acid test, C. Spectrophotometry, D. Hoppe-seyler's test
A: Kastle mayer test
Answer: A: Kastle mayer test 
Explanation: Ans. is 'a' i.e., Kastle mayer testSpectroscopic examination, Hoppe - Seyler's test (10% NaOH), kunkel's (tannic acid) test and adding water (15 ml) in 2 drops of blood can detect CO.