TABLE 8.1.
Clinical Laboratory Tests that Contribute to the Diagnosis of Anthrax
| Type of Test | Specimen | Expected Result |
|---|---|---|
| Nonspecific | ||
| White blood count | Whole blood | Elevated count |
| Cerebrospinal fluid (CSF) analysis | CSF | Normal |
| Presumptive | ||
| Growth on sheep blood | Blood, CSF, lesion | Growth within 24 hours |
| Colony morphology | Bacterial growth | Gray-white colonies, flat or convex, ground glass appearance |
| Gram stain | Bacterial growth | Large Gram-positive rods |
| Hemolysis | Bacterial growth | Clear hemolysis |
| Motility | Bacterial growth | Motile |
| Sporulation | Bacterial growth | Visual spores with malachite green stain |
| Confirmatory | ||
| Capsular stain | Bacterial growth | Visual capsules with M'Faydean stain |
| Gamma phage | Bacterial growth | Lysis by gamma phage |
| Direct fluorescent antibody (DFA) | Bacterial growth | Positive fluorescence |
| Polymerase chain reaction (PCR) | Bacterial growth | Positive PCR |
| Time-resolved fluorescence (TRF) | Bacterial growth | Positive TRF assay |
| Molecular characterization | Bacterial growth | Positive match with control materials |