Critical Values Listing

Critical Values in Microbiology are results that indicate a potentially life threatening condition requiring immediate attention by the clinician. Critical Laboratory results are always reported by telephone immediately.  If any of these come positive, they will be reported to the physician…

Positive Blood Culture initially detects organism by gram stain.

Positive CSF Gram Stain or Culture

Positive Directigen.  Directigen is an antigen, meaning it’s part of the organism, and is a characteristic of it.  You’re using this as a method of identification.  You’re looking for the antigen basically and it’s generally done in blood or blood products.

Positive AFB Smear or Culture indicates tuberculosis or leprosy.

Positive India Ink typically means a negative stain which is done for fungi and is typically associated with meningitis so the specimen of choice is CSF and that identification is done by a Negative stain.

Positive C. difficile Toxin indicates a diagnosis of Pseudomembranous colitis, or as it’s more commonly called, antibiotic associated colitis