Optimal blood test values for diagnosing osteomyelitis

A new study published by one of our much loved DFA 2019 International Speakers – global diabetic foot infection guru and foot cake surgeon extraordinaire, Professor Larry Lavery – has just reported the optimal blood test values for diagnosing diabetic foot osteomyelitis.

The study by Prof Lavery’s group in the US was by far the largest to investigate patients with diabetic foot infections to determine which erythrocyte sedimentation rate (ESR) and/or C-reactive protein (CRP) values most accurately diagnosed (and ruled-out) osteomyelitis confirmed with bone biopsies.

From 353 eligible patients with moderate or severe diabetic foot infections they reported the most accurate blood test values for diagnosing osteomyelitis were an ESR > 60 mm/hr with a CRP level >7.9 mg/dL. They also found that an ESR < 30 mm/hr was the optimal threshold for ruling out osteomyelitis.

Prof Lavery’s group then used their findings to create this very useful clinical diagnostic flowchart below.

But, they do caution that as their study was in patients with moderate or severe diabetic foot infection that their finding may not apply to those with minor diabetic foot infections and those with non-diabetes foot infections as they have also reported before.

Finally, the authors recommend future more comprehensive studies are now needed to inform even more accurate clinical diagnostic flowcharts for foot osteomyelitis that also include probe-to-bone and imaging tests as also recommended by the new IWGDF diabetic foot infection guidelines.

But, we dare say if you attended DFA 2019 you probably had already heard all this from Prof Lavery himself and potentially been super impressed by his foot cake surgical skills along the way ;).