This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abnormal labor, Subject name: Gynaecology & Obstetrics
Blood will interfere with the nitrazine test for detecting ruptured membranes because: 
Select and explain. 
A. It is acid, B. It is alkaline, C. It contains increased amounts us sodium chloride, D. It contains decreased amounts of sodium chloride
B: It is alkaline
Answer: B: It is alkaline 
Explanation: Blood mixes with nitrazine to produce false positive results, as there is increase in ph. It turns the litmus paper to blue suggestive of PROM. TEXTBOOK OF OBSTETRICS, SHEILA BALAKRISHNAN, 2nd EDITION,pg:197