Clinical sign | Negative predictive values* | Likelihood ratios of negative result* |

Nuchal rigidity | 0.62 to 0.80 | 0.56 to 0.74 |

Kernig’s sign | 0.51 | 0.51 to 0.56 |

Brudzinski’s sign | 0.58 | 0.46 to 0.61 |

A quantitative summary of how effectively the absence of each clinical sign alone rules out a diagnosis of meningitis.

↵*Predictive values and likelihood ratios derived from studies summarised in table 1.2 4–7