What are best lab tests for anthrax?

Three types: There is cutaneous, GI and pulmonary the later is the most serious and you could die from it.

This is moot: Anthrax organisms grow on culture. However, a physician must suspect anthrax and treat, because it is likely to kill you -- especially the inhaled form -- before the lab result is back.

No direct test: There is no specific direct test. If a gram stain revealed spores that could help confirm diagnosis. However, spores are often not apparent. Gram positive bacteria on gram stain can change over time. Confirmatory tests include gamma bacteriophage testing, indirect hemagglutination and enzyme linked immunosorbent assay to detect antibodies. Tx based on possible exposure (risk) & presentation.