MiraVista Diagnostics Strives to Continually Improve Fungal Testing

Improved MVista® Histoplasma Antigen Quantitative EIA

At A Glance

  1. MiraVista Diagnostics will soon transition to an improved Histoplasma antigen test.
  2. Urine, serum, plasma, BAL fluid, and CSF can all be tested.
  3. An expanded quantifiable concentration range (0.2 – 20.0 ng/mL) without a ‘below the limit of quantification (BLQ) result facilitates treatment monitoring.
  4. Results are reported the same day the specimen is tested in 90% of specimens.
  5. Advantages of the older test are maintained: high quality results, established role for monitoring treatment [1Wheat LJ, Freifeld AG, Kleiman MB, et al. Clinical practice guidelines for the management of patients with histoplasmosis: 2007 update by the Infectious Diseases Society of America. Clin Infect Dis 2007 Oct 1; 45(7):807-25.], quick turnaround and access to consultants experienced with diagnosis and treatment of histoplasmosis and other endemic mycoses.

The MVista® Histoplasma antigen test is highly sensitive and specific

The MVista® Histoplasma Antigen Quantitative EIA [2Hage CA, Ribes JA, Wengenack NL, et al. A multicenter evaluation of tests for diagnosis of histoplasmosis. Clin Infect Dis 2011 Sep; 53(5):448-54.] (MVista® Histo Ag EIA, test code 310), has changed how we diagnose and monitor treatment of histoplasmosis. For initial testing, urine is the sample of choice. When urine is tested, the MVista® Histo Ag EIA is highly sensitive (92%) and specific (99%) [2Hage CA, Ribes JA, Wengenack NL, et al. A multicenter evaluation of tests for diagnosis of histoplasmosis. Clin Infect Dis 2011 Sep; 53(5):448-54.]. MVista® Histo Ag EIA is validated for antigen detection in urine, serum, plasma, BAL fluid and CSF, an advantage compared to Histoplasma antigen test offered elsewhere.

Testing serum is useful for diagnosis of cases with negative results in urine especially in patients with acute pulmonary histoplasmosis, where up about half of cases may have been missed if only urine was tested [3Swartzentruber S, Rhodes L, Kurkjian K, et al. Diagnosis of acute pulmonary histoplasmosis by antigen detection. Clin Infect Dis 2009 Dec 15; 49(12):1878-82.]. Another advantage of testing serum is that the concentration in serum is usually quantifiable if the sample result in urine is above the limit of quantification (ALQ). In such cases monitoring clearance from serum is recommended until the urine concentration drops into the quantifiable range.

The MVista® Histo Ag EIA is useful for guiding treatment [4Connolly PA, Durkin MM, LeMonte AM, Hackett EJ, Wheat LJ. Detection of histoplasma antigen by a quantitative enzyme immunoassay. Clin Vaccine Immunol 2007 Dec; 14(12):1587-91.] and diagnosing relapse early [5Wheat LJ, Connolly-Stringfield P, Blair R, Connolly K, Garringer T, Katz BP. Histoplasmosis relapse in patients with AIDS: detection using Histoplasma capsulatum variety capsulatum antigen levels. Ann Intern Med 1991 Dec 15; 115(12):936-41], important characteristics lacking in the other commercial Histoplasma antigen detection assays.

The improved MVista® Histoplasma Ag EIA retains the advantages of the older assay: unequaled accuracy, quick turnaround time, and availability of consultants experienced with diagnosis and management of histoplasmosis.

The improved MVista® Histoplasma antigen test has undergone rigorous validation studies

The improved MVista® Histo Ag EIA has undergone rigorous validation testing, and results are impressive. As expected, cross-reactivity occurs in 90% of specimens from patients with blastomycosis [2Hage CA, Ribes JA, Wengenack NL, et al. A multicenter evaluation of tests for diagnosis of histoplasmosis. Clin Infect Dis 2011 Sep; 53(5):448-54.] and 60% with coccidioidomycosis [4Connolly PA, Durkin MM, LeMonte AM, Hackett EJ, Wheat LJ. Detection of histoplasma antigen by a quantitative enzyme immunoassay. Clin Vaccine Immunol 2007 Dec; 14(12):1587-91.].

At MiraVista, quality-control goes beyond test development and validation. There are many layers of safeguards built into the daily testing protocols to ensure that results are highly accurate. Free consultation is provided for questions related to use of these tests for diagnosis and patient management.

REFERENCES:

  1. Wheat LJ, Freifeld AG, Kleiman MB, et al. Clinical practice guidelines for the management of patients with histoplasmosis: 2007 update by the Infectious Diseases Society of America. Clin Infect Dis 2007 Oct 1; 45(7):807-25.
  2. Hage CA, Ribes JA, Wengenack NL, et al. A multicenter evaluation of tests for diagnosis of histoplasmosis. Clin Infect Dis 2011 Sep; 53(5):448-54.
  3. Swartzentruber S, Rhodes L, Kurkjian K, et al. Diagnosis of acute pulmonary histoplasmosis by antigen detection. Clin Infect Dis 2009 Dec 15; 49(12):1878-82.
  4. Connolly PA, Durkin MM, LeMonte AM, Hackett EJ, Wheat LJ. Detection of histoplasma antigen by a quantitative enzyme immunoassay. Clin Vaccine Immunol 2007 Dec; 14(12):1587-91.
  5. Wheat LJ, Connolly-Stringfield P, Blair R, Connolly K, Garringer T, Katz BP. Histoplasmosis relapse in patients with AIDS: detection using Histoplasma capsulatum variety capsulatum antigen levels. Ann Intern Med 1991 Dec 15; 115(12):936-41