Swine-Flu Shakedown

By Josh Carmel

A number of weeks ago I was stricken with the very illness that I repudiated in my first article. Indeed, as my companion in New York had presciently uttered, I had been “swined.” Amidst an eclectic swirl of Nyquil, Motrin, and Robitussin, I began to contemplate a common inquiry among my floor-mates, who had previously contracted the illness: How was swine-flu diagnosed at Gettysburg College and, consequentially, was the test employed valid? Although substantial medication may have marred my clarity during, the results garnered after my illness provide interesting insight into our familiar friend.

Rapid Influenza Diagnostic Tests (RIDTs), the oh-so auspicious nasal swabs executed by our health center, are classified as, according to the Center for Disease Control, antigen detection tests. They distinguish the influenza nucleoprotein antigen, the source of the virus which prompts action by the immune system, and provide pertinent results within a “clinically relevant time period in order to inform clinical decisions,” stated a guideline from the CDC website.

“[The test used by the Gettysburg College Health Center] is the only one you can do in-house,” said Director of Health Services Frederick Kinsella. “The [normal] test takes three days to return.”

While the RIDT utilized by the Health Center provides, if positive, a definitive affirmation of one’s illness, it is fraught with a multitude of false negatives.

“[There are] more false negatives than positives,” continued Kinsella. “We offer to students, when it comes up positive, [that] it’s definitely positive.”

CDC statistics, however, convey that, compared to real-time reverse transcriptase-polymerase chain reaction tests (RT-PCR), a laboratory technique utilized to produce many facsimiles of a DNA sequence, RIDT’s range in sensitivity from 10-70 percent. Such a wide sphere of variance produces an equally vast spectrum of diagnosis, subjecting patients to either false positives or false negatives.

Understanding the limitations, communicated another CDC H1N1 guideline, “of RIDTs is very important to the appropriate interpretation of results for clinical understanding” and subsequently attributes a lower degree of sensitivity to the nasal swap test employed by the Health Center.

Even more pressing, however, is the inability of current FDA approved RIDTs to distinguish between seasonal influenza and swine flu. In fact, according a CDC data compilation, sensitivity for the latter is contingent upon individual clinical laboratory data and ranges from 20-100 percent. The ambiguity propagated by RIDTs suggests that, even upon a negative diagnosis, a general practitioner must not use the data to “send the child back to school” and must still decide, “using clinical symptoms, severity, and underlying disease, whether or not antiviral treatment is appropriate.”

“[Even if the test returns a negative] we may ask the student to isolate themselves [until] we can clinically diagnose them,” Kinsella said.

Although the information provided my seem wholly conventional, failing to answer nagging questions in favor of elaborating upon old ones, the data presented depicts a marked disparity between the sensitivity of laboratory tests and RIDTs.

Despite the rather discrepant sensitivity of RIDTs, indeed I was told that the test was occasionally irrelevant, it has several advantageous qualities. An individual who unequivocally contracts swine flu will almost always return a positive diagnosis, allowing the swift remedy of symptoms and the alleviation of subsequent repercussions. Likewise, a negative diagnosis, although questionable, suggests a mild strain of H1N1 and allows for appropriate treatment.

Even so, as I lingered in the narrow corridors of the Health Center, inundated by a host of necessary precautions and donning a tenacious facemask, one question came to mind—Where did my 15 dollars, necessary for the nasal swab, actually go?