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# Table 2 Calculation of post-test probability using likelihood ratios

1. | Odds = \frac{probability}{1-probability} |

2. | Post-test odds = pre-test odds × likelihood ratios |

For example, according to table 1, post-test probability of uncomplicated UTI in case1 can be calculated as: | |

Pre-test odds = \frac{0.12}{\left(1-0.12\right)}=0.13 | |

Post-test odds = 0.13 × 1.5 × 1.8 × 3.1 × 4 = 4.35 | |

Post-test probability = \frac{4.35}{\left(1+4.35\right)}=81\% |