Trokos

Test library › Foot, ankle & calf

Probe-to-bone test (diabetic foot ulcer)

For: Osteomyelitis under a diabetic foot ulcer

Infection of the bone beneath a foot ulcer in a person with diabetes.

Useful in both directions
Sensitivity87%
Specificity83%
LR+ (positive)5.12
LR− (negative)0.16

Both likelihood ratios calculated from the review's pooled sensitivity and specificity; the review published none.

What the numbers mean

  • Positive result: a moderate rule-in: a positive result makes the diagnosis clearly more likely.
  • Negative result: a moderate rule-out: a negative result makes the diagnosis clearly less likely.

Work out what a result means for your patient: probability calculator

Source

Lam K, van Asten SAV, Nguyen T, La Fontaine J, Lavery LA. Diagnostic Accuracy of Probe to Bone to Detect Osteomyelitis in the Diabetic Foot: A Systematic Review. Clin Infect Dis. 2016;63(7):944–948. Journal article (DOI) · systematic review

Figures as they will appear in Rule It In, Rule It Out (Trokos, forthcoming). If a newer or better study changes them, this page changes with the book. Figures last updated from the book on 6 October 2026.

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This page gives the published figures. Rule It In, Rule It Out adds how to do this test, what counts as positive, how to read the result, and, where studied, whether combining it with other tests helps.

Coming in late 2026 as a PDF and a paperback. Join the list to hear when it's out

One study, one test, once a month

Rule It In is a free evidence letter for musculoskeletal clinicians: one recent study explained, one examination test with its real numbers. From Trokos, publisher of Rule It In, Rule It Out.