There is no blood test that can confirm the diagnosis. Diagnosis requires identifying the mold in the affected tissue by biopsy and confirming it with a fungal culture. Because the causative fungi occur all around, a culture alone is not decisive. Tests may also include culture and direct detection of the fungus in lung fluid, blood, serum, plasma and urine. Blood tests include a complete blood count to look specifically for neutropenia. Other blood tests include iron levels, blood glucose, bicarbonate, and electrolytes. Endoscopic examination of the nasal passages may be needed. Imaging Imaging is often performed, such as CT scan of lungs and sinuses. Signs on chest CT scans, such as nodules, cavities, halo signs, pleural effusion and wedge-shaped shadows, showing invasion of blood vessels may suggest a fungal infection, but does not confirm<unk> . A reverse halo sign in a person with a blood cancer and low neutrophil count, is highly suggestive of<unk> . CT scan images of<unk>  can be useful to distinguish<unk>  of the orbit and cellulitis of the orbit, but imaging may look identical to those of aspergillosis. MRI may also be useful. Currently, MRI with gadolinium contrast is investigation of choice in rhinoorbito cerebral<unk> . Culture and biopsy To confirm the diagnosis, biopsy samples can be cultured. Culture from biopsy samples does not always give a result as the organism is very fragile. To precisely identify the species requires an expert. The appearance of the fungus under the microscope will determine the genus and species. The appearances can vary but generally show wide, ribbon-like filaments that generally don't have septa and that unlike in aspergillosis, branch at right angles, resembling antlers of a moose, which may be seen to be invading blood vessels. File:Zygomycosis,<unk>  2.Ribbon-like hyphae which branch at 90° File:Zygomycosis<unk>  (13430751363).Hyphae in blood vessel File:Mature sporangium of a Mucor sp. fungus.Mature sporangium of a Mucor Other Matrix-assisted laser desorption/ionization may be used to identify the species. A blood sample from an artery may be useful to assess for metabolic acidosis. Differential diagnosis Other filamentous fungi may however look similar. It may be difficult to differentiate from aspergillosis. Other possible diagnoses include anthrax, cellulitis, bowel obstruction, ecthyma gangrenosum, lung cancer, clot in lungs, sinusitis, tuberculosis and fusariosis.
Mucormycosis
Cavernous sinus thrombosis
Chromoblastomycosis
Aspergillosis
Basidiobolomycosis
Orbital cellulitis
Entomophthoramycosis
Talaromycosis