Impact and cost of the serum galactomannan assay at a tertiary care facility.
BACKGROUND
Invasive aspergillosis carries a high mortality with a rising prevalence in immunocompromised hosts. Diagnosis of invasive aspergillosis is challenging and delays in treatment are associated with poor outcomes. The galactomannan assay (GM), a non-culture-based surrogate marker of fungal infection, is widely used in diagnosis. It is unknown whether this assay impacts clinical decision making. We evaluated whether GM testing results in earlier initiation of antifungal therapy and is cost effective.


METHODS
We carried out a retrospective review of the electronic medical records of all patients undergoing GM at a 907-bed tertiary-care general hospital from July 11, 2011, to June 12, 2012. Records of patients with a positive GM were individually reviewed to determine the timing of the assay result, presence and timing of relevant culture data, whether BAL GM was performed, radiology data consistent with invasive aspergillosis, and the timing of initiation of antifungal therapy. For each case, it was determined whether GM results impacted the decision to initiate antifungal therapy.


RESULTS
Forty-six nonduplicate GM samples were positive (>0.5) of 1419 performed. Results were considered to be false positives in 18 cases by care teams. In 21 cases, antifungal therapy was initiated before the assay result based on clinical suspicion, culture data, and/or radiology. The serum GM was performed 164 times at a cost of $21,789 for a single positive result effecting modification of patient care.


CONCLUSIONS
Serum GM testing at a tertiary-care institution is commonly used but infrequently impacts clinical decision making with major financial burden.
1 Department of Pulmonary and Critical Care and Department of Infectious Disease University of Rochester Medical Center, Rochester, NY. 2 Transplant Infectious Diseases and Immunocompromised Host Program, Division of Infectious Disease, Transplant Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA. 3 Address correspondence to: Paritosh Prasad, M.D., D.T.M.&H., Department of Pulmonary and Critical Care and Department of Infectious Disease, University of Rochester Medical Center, 601 Elmwood Avenue, Box 692 Rochester, NY 14642.
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D000328:Adult; D000935:Antifungal Agents / Q000627:therapeutic use; D000946:Antigens, Fungal / Q000097:blood*; D002648:Child; D003362:Cost-Benefit Analysis; D057286:Electronic Health Records; D005690:Galactose / Q000031:analogs & derivatives; D017048:Health Care Costs; D006801:Humans; D016867:Immunocompromised Host; D055744:Invasive Pulmonary Aspergillosis / Q000191:economics* / Q000382:microbiology*; D008351:Mannans / Q000097:blood* / Q000191:economics; D012189:Retrospective Studies; D062606:Tertiary Care Centers; D016896:Treatment Outcome
D000935:Antifungal Agents; D000946:Antigens, Fungal; D008351:Mannans; C012990:galactomannan; D005690:Galactose