Final answer:
The best diagnostic test to confirm or exclude a diagnosis of osteomyelitis in a 5-year-old boy with right hip pain is a blood culture, which can detect the bacteria causing the infection. Other tests, such as a complete blood count, might indicate inflammation but are not definitive for osteomyelitis.
Step-by-step explanation:
Best Diagnostic Test for Osteomyelitis
A 5-year-old boy presenting with right hip pain may be suspected of having osteomyelitis. The best diagnostic test to confirm or exclude a diagnosis of osteomyelitis is typically through a blood culture. Blood cultures are used to detect the presence of bacteria or fungi in the blood and can identify the cause of an infection. This is especially important as osteomyelitis is often caused by a bacterial infection. The most common cause of both septic arthritis and osteomyelitis is the bacterium Staphylococcus aureus. In some cases, additional diagnostic tests such as magnetic resonance imaging (MRI) or a bone biopsy may be necessary to confirm the diagnosis of osteomyelitis.
While a complete blood count with differential can indicate inflammation and the presence of infection, and the erythrocyte sedimentation rate can show the presence of inflammation in the body, neither of these tests can confirm osteomyelitis directly like the blood culture can. Serum glucose is typically not helpful in diagnosing osteomyelitis, unless monitoring for conditions such as diabetes that can increase the risk of infection. In any suspected case of infection, particularly in vulnerable populations such as children and diabetic patients like in our scenarios, timely identification through the appropriate diagnostics is critical for effective treatment.