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Digging into the nuance of labs

functional medicine Sep 02, 2022

One thing I get asked about A LOT from patients and my medical trainees (med students, residents, and fellows) is about the role of testing in the role of diagnosing allergies, autoimmunity, and other invisible illnesses. 

Testing can take several different forms from blood work to imaging studies and procedures. 

When it comes to testing, I come back to a few questions time and time again. 

  1. How might our thinking and/or treatment change based on the possible outcomes? Will it change our management or expectations?
  2. How good is the test at distinguishing real disease from false alarm? Is it a good test? 
  3. What potential harm or benefit may result from a test? What are the costs- money, time, follow-up testing, short and long-term? 

It is probably not surprising that my opinions on obtaining testing have evolved over the course of my training, career, and even more so as a patient. And it varies based on the person, the test, timing... 

 

When I was pregnant with Oliver, I shared a bit about my personal experiences with this thought process and decision-making on the blog (you can read more here). 

Professionally, as a brand new attending allergist, I recall having a pretty hard stance on not performing food allergy scratch testing in situations that were not consistent with true food allergy.

But the reality is, despite my explanations, many patients are still fraught with worry and anxiety that it seems a quick and simple scratch test can deliver (unless there is a false positive skin test in which case then I am back to explaining again..see this is a big problem with food allergy testing- LOTS of false positives)

 

Over the last few years though I have evolved into my own style of practice.

It has become less rigid and more nuanced.

A style that I hope strikes a balance between both listening to my patients’ concerns and worries while also maintaining my professional integrity and understanding of the science. 

 

The biggest issue is that this style of medicine takes a lot longer than black and white medicine. It is much easier, quicker, and cost-effective to just order all the tests or not order any of the tests. 

Navigating the nuance and wading into the gray areas… that takes more mental effort, more time, and patience. 

 

It requires that we slow down and talk to our patients. 

To try our best to understand what their experiences are. 

What their worries and anxieties may be. 

Especially when we can’t exactly explain what might be causing those symptoms or when we don’t know the answer. 

 

I also struggle when I see patients bring in labs that I am not trained to interpret or when I don’t agree with their use.

Again this is in part the gray area but also related to navigating difficult conversations.

If I am just meeting a patient and then tell them I think their trusted advisor (blogger, friend, alternative medicine practitioner) is full of... baloney.

Well, you can see how this could be delicate depending on the context right? 

Living up to the "do no harm" can take on new and different meanings.

 

Before I get to a few examples I want to share a few definitions that are helpful in this discussion. 

CLIA- Clinical Laboratory Improvement Amendments Regulations: 

CLIA regulations require any laboratory that performs testing on patient specimens to have an appropriate CLIA certificate and to meet applicable quality and analytic standards to ensure accurate and reliable test results. CLIA regulations, however, do not address the clinical validity of testing (i.e., the accuracy with which the test identifies, measures, or predicts a patient's clinical status). CLIA is helpful to tell us that the lab is run well from a logistics standpoint but doesn't tell us anything about whether the test is a "good test" or not. 

Food and Drug Administration clearance

FDA clearance or approval of a test provides assurance that the test has adequate analytical and clinical validation and that it is safe and effective. This lets us know that the test has reached a benchmark in amongst science professionals.  This may not be the case with newer testing modalities yet. 

 

I’ll share a few examples and my current takes on them: 

  1. Mold or mycotoxin testing- not FDA approved. What makes this area extra murky is that we don’t know what is a safe or unsafe level of exposure to molds or mycotoxins. Molds are pretty ubiquitous and certainly can be associated with health effects but the best way to confirm these effects accurately is problematic. There are A LOT of folks invested in this area and A LOT of money to be made on shaky data. 
  2. Food sensitivity testing- not FDA-approved and science suggests that foods that do come up “positive” on testing may actually indicate tolerance to that food. My prediction is that at some point we will have an approach that takes our gut microbiome, enzymes, and other factors into account. In the meantime, you are better off keeping a food & symptom journal. 
  3. Heavy metal testing- We test for lead poisoning routinely in children. Mercury is another heavy metal that we can encounter at elevated levels especially if we eat a lot of fish. Ferritin is a good measure for iron stores and can be elevated in inflammatory states or low in the setting of iron deficiency. 
  4. 24- hour adrenal stress index- not FDA-approved and this is supposed to diagnose adrenal fatigue but multiple peer-reviewed studies have debunked this as an actual diagnosis. Are many of us living in constant fight or flight? Yes. Does it cause our adrenal glands to produce less hormones? No.  
  5. Inflammation labs- are fraught with challenges and nuance. They need to always be taken into context with what the patient is experiencing. Many of the labs we order like C-reactive protein, Sed Rate (ESR) and ferritin are non-specific. Also, autoimmune antibody studies tend to have relatively low sensitivity and specificity which means they are negative in some people who have the disease and are positive in some people who don’t have the disease. 

 

So why is this all so important? 

Because there is so much misinformation everywhere but especially online!  

Even in areas of medicine that are pretty well understood and are not too controversial, like seasonal allergies! 

A new study recently demonstrated that 36% of YouTube videos contain misleading information about hay fever and only 43% contained useful information. Check it HERE. 

It is really hard to find a place that will dig into the facts and is willing to navigate the nuance required of the gray areas.

 

Starting TODAY, you can now subscribe to the Crunchy Allergist YouTube channel where we aim to do both while tackling topics in the area of allergies, autoimmunity, and anti-inflammatory living!

Let me know what topics you want to see covered or guests you would love to hear from by sending us an email at [email protected]

To borrow from the psychologist, Adam Grant, I look forward to getting curious, re-thinking, learning & un-learning as we go!