This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Special topics, Subject name: Forensic Medicine
All of the following are screening tests for blood except 
Select and explain. 
A. Leucomalachite green test, B. Phenolphthalien test, C. Takayama crystal test, D. None of the above
C: Takayama crystal test
Answer: C: Takayama crystal test 
Explanation: Crystal Tests Crystal tests are regarded as confirmatory tests. These tests involve the non-protein heme group of hemoglobin, called porphyrins. Haemochromogen Crystal Test (Takayama test): Place a small piece of suspected material on a glass slide and add 2 to 3 drops of Takayama reagent (sodium hydroxide, pyridine, glucose), and cover with a coverslip. Pink, feathery crystals of haemochromogen or reduced alkaline haematin arranged in clusters, sheaves, etc., appear in one to six minutes. Slight warming of the slide hastens the reaction. The result is negative if crystals are not formed in 30 minutes. The test gives good result even with old stains. It is delicate and more reliable. Ref:- k s narayan reddy; pg num:-451, image plate 12