Blood will interfere with the nitrazine test for detecting ruptured membranes because:
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
It is acid
It is alkaline
It contains increased amounts us sodium chloride
It contains decreased amounts of sodium chloride
Abnormal labor