David's New Book

Monday, September 9, 2013

Rapid Diagnostics - Not!




This topic keeps coming up.  I hear about it during the planning stages of clinical trials, from fellow ID clinicians who want to avoid broad spectrum empiric therapy or to de-escalate from such quickly in order to reduce resistance, and, occasionally, from small companies peddling rapid diagnostics. The Infectious Diseases Society and FDA held a workshop on the topic a few years ago.  We heard about nucleic acid based approaches, rapid serology, rapid this and that.  There were three key problems that were raised.  First, the regulatory path in the US is anything but straightforward – especially if you wanted to link a diagnostic with an antibiotic (but why would we do that?). Second, industry is not interested (at least in the US) because (a) the regulatory hurdles are high and (b) they are skeptical that they would ever make a return on their investment (the situation is different in Europe where the regulatory approach to diagnostics is easier and therefore so is the return on investment). But, most importantly, at least to me, rapid diagnostics are not rapid – far from it – again – especially in the US.  What am I talking about?  FDA requirements? Technological barriers? Nope.

I’m talking about the rope a dope system currently in place in US hospital laboratories and on hospital wards in the US. To understand this, you have to take a trip with me down memory lane.  When I was training as a medical student at the county hospital in Cleveland, we were expected to have done all the appropriate diagnostic tests ourselves on the patient to rule out or in the most likely diagnoses on our list of differential diagnoses by the morning after admission.  That meant – all appropriate specimens collected, Gram stains performed and read and cultures plated – by us!  We even had to collect and stain bone marrow specimens if the patient had new anemia.  The infectious diseases service would come by in the afternoon the next day and review our Gram stains with us.  They would also check our culture plates (which had been incubating in an incubator adjacent to the ward) overnight and they would point out colonies and help interpret the cultures immediately.  Of course, those were the days when infectious diseases fellows were expected to be able to read Gram stains and interpret growing cultures of microorganisms from patient specimens. 

Those days, unfortunately in my view, are long gone.  Law suits and the federal government have seen to that. The Clinical Laboratory Improvement Amendments (CLIA) law was passed in 1988. Under this law, only certified laboratories and laboratorians are allowed to report clinical laboratory results in the US.  This law was supported by hospitals desiring to limit lawsuits, but laboratory workers trying to protect their jobs and by patient advocates thinking that this would mean better care. This meant that our county hospital in Cleveland had to remove all the laboratories they had carefully constructed adjacent to each patient ward.  Physicians could still see Gram stains and cultures, but only if they did so in the official clinical laboratory – and their interpretations could not become part of the patient record. Logistically, what does this mean?  A specimen is collected from the patient by the physician, nurse or technician, and is placed in an outbox on the ward. The specimen then has to be transported to a laboratory – which may or may not be on site in the same hospital where the patient is located.  On arrival in the laboratory, the specimen is labeled and entered into some tracking system by someone – then, eventually, is processed.  Is the lab open 7/7 24/24?  Most are not. When I was training – I (or someone) was definitely available 7/7 and 24/24. Once the specimen is processed – if there is a rapid test available in the laboratory – that test could be performed and the results reported to the caregiver. But you get the idea.  Even the most rapid of tests that can be completed within say 3 hours usually take at a minimum 8 hours and, overnight – 12 hours and, over a weekend – who knows how long?

So our biggest challenge is ourselves!  Our hospital bureaucracy, the laboratory workers and
many healthcare advocates are all conspiring to make rapid diagnostics logistically less useful than they might be.  Imagine if a machine was available on the ward and that there was a designated nurse trained to use the machine available (and with time) to operate such a machine during each nursing shift. What a difference that would make.  When will we get there? We have already gotten there for an office-based test to detect strep throat – waived for CLIA requirements.  What about for hospital-based tests? You tell me!