It can be challenging just to get a doctor to understand that you need a test for Valley Fever, even in the worst places for the epidemic. Some doctors don’t listen. Some doctors want to believe every other disease must be the cause of your symptoms before even testing for Valley Fever. Some patients wait years without a proper test, let alone proper treatment.
But how good are the Valley Fever blood tests once they are used? A recent study evaluated Mira Vista Diagnostics’ new MVista anti-Coccidioides antibody enzyme immunoassay testing system in comparison to other test kits on the market.
Enzyme Immunoassay may be written as EIA or often just as “Coccidioides Ab” (short for antibody test) in your lab results. An article in Medical Mycology recently compared the MVista test two other EIA Coccidioides test kits.
EIA Test Kit Accuracy
MVista EIA …87.4%
Meridian EIA …70.9%
IMMY Omega …46.6%
An earlier article compared the MVista test with immunodiffusion tests and complement fixation titer tests. These different types of tests examine the blood differently but should still be able to provide a positive or negative result.
Comparitive test accuracy
MVista EIA …88.3%
CF Titer …66.1%
A positive fungal culture is the most accurate and reliable way to diagnose coccidioidomycosis. Some tests may have their uses. For example, “quantitative” tests like complement fixation titers can show how bad an infection is or track how well things are improving as the test results change at different times. The MVista EIA is “semiquantitative” and does not have the extensive history of use to track a patients’ infection as the CF titers do, so there may be grounds to use one particular type of test over another.
However, with some fairly low rates of accuracy in the testing, these results underscore the relatively high risk that tests could fail. The type of test kit chosen by your lab may also be more error prone than others.
This article may be useful to share with your medical team so they can consider the best tests for you.
Malo J1, Holbrook E2, Zangeneh T1, Strawter C1, Oren E1, Robey I1, Erickson H1, Carranza-Chahal R1, Durkin M2, Thompson C1, Hoover SE3, Ampel NM1, Wheat LJ2, Knox KS1. Comparison of three anti-coccidioides antibody enzyme immunoassay kits for the diagnosis of coccidioidomycosis. Med Mycol. 2020 Apr 11. pii: myz125.
Malo J1, Holbrook E2, Zangeneh T3, Strawter C3, Oren E3, Robey I3, Erickson H3, Chahal R3, Durkin M2, Thompson C3, Hoover SE4, Ampel NM3, Wheat LJ2, Knox KS3. Enhanced Antibody Detection and Diagnosis of Coccidioidomycosis with the MiraVista IgG and IgM Detection Enzyme Immunoassay. J Clin Microbiol. 2017 Mar;55(3):893-901. doi: 10.1128/JCM.01880-16. Epub 2017 Jan 4.