Eating popsicles may cause false positive fungal test -
A woman tested positive for a serious fungal infection, but wasn't actually infected instead, her test results stemmed from eating ice pops containing a certain food additive, according to a case report.
The tests said the patient had aspergillosis, a dangerous infection caused by mold, but doctors couldn't find any other symptoms. A CT scan didn't find any trace of the fungus in the patient's body, and blood samples didn't contain the fungus, either.
Mysteriously, the patient continued to test positive over three consecutive days.
The doctors treated the woman with antifungal drugs before realizing that the test for aspergillosis also picks up on a food additive used in ice cream. The patient had been eating three to four flavored ice pops daily.
Although the ice pop connection came as a surprise to the woman's doctors, they knew of other reports of false-positive test results due to food products, said Dr. Nicolas Guigue, a pharmacologist at Saint Louis Hospital in Paris, who wrote about the woman's case in a report published July 4 in the New England Journal of Medicine. [Microscopic Worlds Gallery: Fascinating Fungi]
The test for aspergillosis looks for a fiber called galactomannan, which makes up the cell walls in the fungus. The same fiber is used in ice pops and ice cream as a thickener and stabilizer, to make them melt better. (This does not mean that ice pops contained mold.)
"Physicians should be aware of this unusual cause of interaction with the galactomannan test, which can result in unnecessary investigations and treatments," Guigue and colleagues wrote in the report.
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