Diagnosis

Doctors often order several tests to try to pinpoint underlying infection.

Blood tests

Blood samples are used to test for:

• Evidence of infection
• Clotting problems
• Abnormal liver or kidney function
• Impaired oxygen availability
• Electrolyte imbalances

Other lab tests

Other lab tests to identify the source of the infection might include samples of:

• Urine
• Wound secretions
• Respiratory secretions

Imaging tests

If the site of infection is not readily found, your doctor may order one or more of the following imaging tests:

• X-ray. X-rays can identify infections in your lungs.
• Ultrasound. This technology uses sound waves to produce real-time images on a video monitor. Ultrasound may be particularly useful to check for infections in your gallbladder and kidneys.
• Computerized tomography (CT). This technology takes X-rays from a variety of angles and combines them to depict cross-sectional slices of your body's internal structures. Infections in your liver, pancreas or other abdominal organs are easier to see on CT scans.
• Magnetic resonance imaging (MRI). This technology uses radio waves and a strong magnet to produce cross-sectional or 3D images of the internal structures of your body. MRIs may be helpful in identifying soft tissue or bone infections.