Article China Enterovirus A71 Hand, Foot and Mouth Disease Humans Molecular Diagnostic Techniques Nucleic Acid Amplification Techniques Polymerase Chain Reaction Sensitivity and Specificity area under the curve diagnosis diagnostic accuracy diagnostic test accuracy study diagnostic value false negative result false positive result feces analysis hand foot and mouth disease human intermethod comparison loop mediated isothermal amplification loop-mediated isothermal amplification medical research meta analysis meta-analysis molecular diagnosis nucleic acid amplification polymerase chain reaction procedures publication bias