Diabetic foot laboratory findings

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Anahita Deylamsalehi, M.D.[2]

Worsened glycemic control could be seen in the laboratory evaluation of diabetic foot patients. Even in the presence of infection, there is no guarantee that measures such as White blood cells (WBC), Erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) be elevated. For detection of the main responsible microorganisms biopsy, curettage, or aspiration, a tissue sample is recommended. It is recommended to obtain a sample from discharge of the ulcer‘s base. Moreover, due to contamination of all ulcers, culture from non-infectious ulcers is not recommended. For confirming osteomyelitis diagnosis and for appropriate antibiotic treatment, it is critical to obtain a bone biopsy. Properly obtained specimens for culture prior to initiating empiric therapy provide useful information for guiding antibiotic selection, particularly in those with chronic or previously treated infections which are commonly caused by gram-negative bacilli or obligate anaerobic organisms.

• Even in deeply infected ulcers, laboratory measures such as WBC, ESR and CRP might be normal. Nevertheless, elevated measures demonstrate infection.^[1]
• Presence of infection in diabetic ulcers can worsen the glycemic control.^[2]
• For detection of main responsible microorganisms biopsy, curettage, or aspiration, a tissue sample is recommended. It is recommended to obtain a sample from discharge of the ulcer‘s base. Moreover, due to contamination of all ulcers, culture from non-infectious ulcers is not recommended.^[3]
• For confirming osteomyelitis diagnosis and for appropriate antibiotic treatment, it is critical to obtain a bone biopsy.^[4]

• Properly obtained specimens for culture prior to initiating empiric therapy provide useful information for guiding antibiotic selection, particularly in those with chronic or previously treated infections which are commonly caused by gram-negative bacilli or obligate anaerobic organisms.^[5][6]

• Infected wounds should be cultured by obtaining tissue samples during any surgical procedure or by tissue biopsy or wound base curettage.
• Bone cultures are optimal for detecting the pathogen in osteomyelitis, but blood cultures are only necessary for those with a severe (grade 4) infection.
• Cultures may be unnecessary for mild infections in patients who have not recently received antibiotic therapy and who are at low risk for methicillin-resistant Staphylococcus aureus (MRSA) infection; these infections are predictably caused solely by staphylococci and streptococci.
• Cultures may yield organisms that are commonly considered to be contaminants (eg, coagulase-negative staphylococci, corynebacteria), but these may be true pathogens in diabetic foot infection and are often resistant to the empiric antibiotics.