Diagnosis

Your doctor may feel the area around the affected bone for any tenderness, swelling or warmth. If you have a foot ulcer, your doctor may use a dull probe to determine the proximity of the underlying bone.

Your doctor may order a combination of tests and procedures to diagnose osteomyelitis and to determine which germ is causing the infection. Tests may include:

Blood tests

Blood tests may reveal elevated levels of white blood cells and other factors that may indicate that your body is fighting an infection. If osteomyelitis is caused by an infection in the blood, tests may reveal which germs are to blame.

No blood test can tell your doctor whether you do or don't have osteomyelitis. However, blood tests can give clues to help your doctor decide what additional tests and procedures you may need.

Imaging tests

• X-rays. X-rays can reveal damage to your bone. However, damage may not be visible until osteomyelitis has been present for several weeks. More-detailed imaging tests may be necessary if your osteomyelitis has developed more recently.
• Magnetic resonance imaging (MRI). Using radio waves and a strong magnetic field, MRI scans can produce exceptionally detailed images of bones and the soft tissues that surround them.
• Computerized tomography (CT). A CT scan combines X-ray images taken from many different angles, creating detailed cross-sectional views of a person's internal structures. CT scans are usually done only if someone can't have an MRI.

Bone biopsy

A bone biopsy can reveal what type of germ has infected your bone. Knowing the type of germ allows your doctor to choose an antibiotic that works particularly well for that type of infection.

An open biopsy requires anesthesia and surgery to access the bone. In some situations, a surgeon inserts a long needle through your skin and into your bone to take a biopsy. This procedure requires local anesthetics to numb the area where the needle is inserted. X-ray or other imaging scans may be used for guidance.