Exams and Tests

A careful medical history, physical exam, and other tests are necessary to diagnose hantavirus pulmonary syndrome (HPS). These other tests may provide helpful information in the early stages of HPS or when there are breathing problems caused by HPS. But some test results may be normal during the early course of HPS and may not become abnormal until severe illness occurs.

The following tests may help determine whether HPS is causing your symptoms:

• Complete blood count (CBC). A complete blood count (CBC) may be done to determine whether the white blood cell count is increasing, indicating that an infection may be present, or the platelet count is decreasing (thrombocytopenia). A CBC also may be done to check for a rising hematocrit level.
• Oxygen saturation.Pulse oximetry or arterial blood gas (ABG) tests may be done to determine whether the amount of oxygen in the blood is adequate. ABG tests also may identify increased levels of acid in the blood (acidosis).
• Chest X-ray. A chest X-ray may be done if the amount of oxygen in the blood (as determined by ABG or pulse oximetry) is less than 90%, especially if you are having difficulty breathing. An X-ray also may be done if you have signs of pulmonary edema.

Other tests that may be done include:

• An enzyme-linked immunosorbent assay (ELISA), to detect antibodies to hantaviruses in the blood. If these antibodies are found, they may show if you are currently infected or were infected in the past.
• Prothrombin time (PT) and partial thromboplastin time (PTT), to determine how long it takes the blood to clot.
• Tests to help confirm or rule out other causes of the infection, such as viral influenza (flu) or infectious mononucleosis (mono).

If your condition gets worse and you are admitted to an intensive care unit (ICU), more tests will be done to identify the cause of your symptoms.