Behind the Numbers

By: Marcus Hopkins, Blogger

In the eight months that I’ve been writing for HEAL Blog, I have often advocated the position that everyone should be tested for HCV or that testing should be offered to every patient whenever they visit a doctor. On several occasions, after the publication of a piece in which I proposed this scope of testing, I have been challenged by colleagues, healthcare professionals, and former professors on the matter, their arguments being that such broad screening without any known risk factors poses a significant risk of returning “false positives” – tests that mistakenly come back positive for HCV without a patient actually being infected – and also that screening on such a broad level would place too great a strain on already limited resources, both financial and human.

As someone who grew up in the midst of the initial HIV/AIDS outbreak in the 1980s and 90s, I have always operated from a position where I suggest, “Knowing is better than not knowing.” When scientists finally discovered a way to screen for HIV, this theme became common amongst those of us who saw firsthand the devastation wrought at the hands of AIDS. Even today, I always suggest in every guest lecture that everyone get tested for HIV every six months, whether or not there is a “scare” (a broken condom, a poor decision, or a thought out decision). I make no judgments about the circumstances; I simply care that, if there is an ill, there is a will to treat it.

But, every time I am challenged on this stance as it relates to HCV, I am taken aback – not because I believe that my colleagues are incorrect in their assertions, nor out of any sense of ego – it is truly because I have to wonder if, at this stage in our technological and scientific history, “false positives” are really an issue, and also if resources are truly so scare that we cannot offer screening on a broader scale.

In order to allay my own fears that I may be advocating a position that is untenable, I decided to look into how we test for HCV to see if the process was as simple as I assumed it to be. I know it sounds silly to think of this at this late stage in the game, but in all of my lectures and outreach, I only ever really talked about testing for HIV, and the ease with which those tests are administered. Never once did it occur to me that the process could be different for HCV, as they are both blood borne pathogens that produce antibodies that are relatively easy to identify. Much to my relief, I discovered that the processes are, in fact, virtually identical for the two viruses.

For both diseases, OraSure Technologies, Inc. offers a quick testing device called “OraQuick.” While the name is the same for both viruses, the process is slightly different:

For HIV testing, the OraQuick device is an orally administered swab that collects oral fluid (similar to, but slightly different than saliva) collected from the gumline to test for HIV antibodies. Once the sample is collected, results can be returned within twenty minutes, making the process quick and easy. If the result comes back “Reactive,” a secondary confirmatory test is required to check to ensure that the results are accurate. The secondary testing is an RNA test, usually the Western blot test, which requires a blood sample being drawn and sent to a laboratory for screening.

OraQuick HVC Test KitThe FDA approved a similar OraQuick device in February of 2011 for use in testing for HCV. Unlike the HIV device, the OraQuick HCV requires a fingerstick collection method, whereby the patient’s finger is pricked and a blood sample is collected. The sample is then mixed in a buffer, the device is inserted into the buffer, and within 20 to 40 minutes, a result should show up as “Reactive” or “Non-Reactive.” If the test returns a “Reactive” result, once again, a secondary confirmatory test is needed to confirm whether or not a patient tests positive for HCV.

The OraQuick HIV testing device boasts greater than 99% agreement with the Western blot confirmatory test, while the OraQuick HCV boasts 98% accuracy with confirmatory tests. This level of accuracy for testing is something that we in the healthcare profession can rely on for accurate testing, and should provide us with the confidence we need to assure our patients and clients that the tests are reliable enough for widespread testing.

Given the ease and accuracy with which HCV testing can be administered, there really is little reason that screening should not be conducted (or at least offered) on a broader basis. Of course, as each state and institution generally procures contracts for purchasing devices in bulk, the issue of financial resources would have to be hammered out in the negotiation process. That said, I’m not certain that the risk of “false positives” is high enough to warrant any real concerns that testing should be limited to a specific set of risk factors.

Part of why I embarked on this discovery mission was that I wanted to ensure that I was giving timely, accurate, and credible information as an advocate and educator. Whenever I encounter a question about why I advocate a specific position, I like to educate myself in order to provide an answer that can address any concerns that may arise. I always appreciate it when my colleagues provide me with an opportunity to expand my knowledge base, and in this case, I leave the process feeling much more confident that I am advocating for something that is both tenable and sound advice.

Disclaimer: HEAL Blogs do not necessarily reflect the views of the Community Access National Network (CANN), but rather they provide a neutral platform whereby the author serves to promote open, honest discussion about Hepatitis-related issues and updates.

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1 Comment

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One response to “Behind the Numbers

  1. JamesInCA

    The approval and clinical success of sofosbuvir (Sovaldi) since December 2013 will, or at least should, cause significant re-evaluation of HCV testing recommendations. Prior treatments were onerous, with iffy cure rates, for a disease typically progressing slowly over many years. Many testing positive would not be recommended to undergo the prior treatment regimen. Sofosbuvir offers a remarkable, almost unprecedented thing: a relatively reliable, outright cure to a viral disease. But with the treatment costing upwards of $80k, insurance companies probably aren’t anxious for a burst of testing that would yield lots of candidates for treatment.

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