infections
Plague and Other Yersinia Infections
Diagnosis of Plague
Examination and culture of samples of blood, sputum, or pus Sometimes other blood tests Rapid diagnosis of plague is important because the longer treatment is delayed, the higher the risk of dying. To diagnose plague, doctors take samples of blood, sputum, or pus from lymph nodes. Samples are examined under a microscope and sent to a laboratory to grow (culture) bacteria. The blood sample is also tested for antibodies to the bacteria. Tests that rapidly detect the bacteria or its genetic material (DNA), such as polymerase chain reaction (PCR), may be done. If doctors suspect pneumonic plague, a chest x-ray is taken. 