My Metametrix Test 

Two female pinworms next to a ruler. The marki...

(Photo credit: Wikipedia)

I was relieved when my Metametrix test came back negative for parasites.  Whew.  Off the worm-hook.  I have a friend whose young daughter has been diagnosed and treated for parasites several times over by a naturopath.  That just doesn’t make sense to me.  I don’t know what to think about that.  As a medical doctor turned stay-at-home mom, I still carry my standard medical biased thoughts toward parasites.

Before we proceed, when medical doctors talk about parasites, the conversation is usually about helminths (worms) or protozoa.  Lice, scabies, and bedbugs are also parasites (ectoparasites–they live outside of you), but not included commonly in this type of discussion.  Bacteria (example H. pylori), yeasts (Candida), and viruses, although you may see them called “parasites”, are not what medical doctors have in mind during a parasite discussion.

To sum it up, this is what I think American medical doctors believe.  Our patients can and do get parasites.  They usually get them from trips abroad, eating poorly cooked meats, daycare, or drinking unclean water from a stream.  We will test for parasites if a patient requests us to or if symptoms and medical history suggest a parasitic infection in our minds; headaches, fatigue, and depression usually don’t count as “good” parasitic symptoms.  Some parasitic infections we don’t even bother testing for.  For example, if history and contact exposure suggest pinworm in a child, many doctors don’t need a “tape test” or stool for ova and parasite.  Only 5% of people with pinworm will have it detected in their stools anyhow. (1)

I do think we have a tendency to scorn natural medicine for overfocusing on parasites and overtreating them.  However, we are well aware of the fact that parasites can and do cause HORRIBLE, deadly, incapacitating diseases, but we discredit them causing these vague illnesses that we have worked up and found no cause for.

Parasites are actually a routine part of human life.  Incredibly, our GI tracts may depend on parasites for proper development.  Most of us, yes even you, have had a parasitic infection in the past and not even known it.  Our wonderful bodies contained and removed the issue.  We didn’t have significant symptoms.  Conversely, some parasites we humans pick up are known to be pathological and cause discrete symptoms, at times dangerous symptoms, and need to be treated with medicine.


Do not use this blog for diagnosis and/or medical advice.  All health concerns should be properly addressed with your physician.


Oh, yuck.  I could really have a parasite?

It is really hard, when in the middle of the thrux of stomach pain, bloating, diarrhea, constipation, proctitis, and headaches, to hear a medical doctor have no explanation other than irritable bowel syndrome, chronic constipation, or some other “waste basket” term.  A patient, me included, will go searching to find their own explanation for their illness.

Here come parasites to the diagnostic rescue.  There are plenty of internet posts devoted to parasite discussion that can make you lose sleep and sanity.  PAR-A-SITE.  “Parasite cleanse” and “parasite purge”, we love you.

Although I really would like to fix my GI tract and mild headaches (for lack of a better word), I want to endeavor to be logical, reasonable, and practical.  I do not want to buy into frenzy, overstatements, and inaccuracies.  I have just about never felt loopier than when I was pushing stool around with a long, rolled piece of toilet paper, looking for all these things described by websites as parasites.  Parasite-a-phobia had to stop.  It is not my friend.

Yuck.  Could I really have a parasite?  Yes.  At some point in life for sure.

Parasitic infections are often and usually quite transient.  For example, a pinworm infection, which children routinely acquire, will be self-limiting and eventually go away after about 6 weeks; Giardia lamblia typically runs its course and resolves after 2-4 weeks. (1)

Another more personal example.  I grew up on a farm with numerous barn cats that, as a child, I loved to chase down, tame, and play “cat circus” with.  Cats carry Toxoplasmosis, a parasite that can infect humans, and it is a very dangerous parasitic infection for a pregnant woman’s fetus.  VERY dangerous.  For young, healthy kids, Toxoplasmosis generally poses nothing more than a cold-like syndrome.

When I was pregnant, I asked my obstetrician to please check my antibody titers to see if I had had toxoplasmosis and chicken pox before; I wanted to be able to relax when I cared for children with rashes at work or when I went home to the farm to visit the cats.  If my antibodies showed I had fought these infections before, the likelihood of me getting them again would be nil.  Sure enough.  I had had toxoplasmosis (and chicken pox) as a child and didn’t know it.  Don’t remember it.  At some point in my life, my body had come in contact with, and appropriately taken care of Toxoplasmosis.  This is just an example of how we get parasitic infections and don’t even know it.

Tests for Parasites

As a medical doctor, I was never trained to go full force looking for parasites.  If a patient had a history and symptoms consistent with a parasitic infection (travel abroad, camping trips, unpasteurized milk, etc), I would order a stool for ova and parasite on three stool specimens collected over three days (“stool for O&P X3” is what I’d write on the lab order form) to be looked at under a microscope and cultured.  The stool test is notoriously insensitive, and sometimes, we just treat a patient based on symptoms, such as in the case of pinworms in children and the rest of their family or in a camper who comes back with diarrhea.

Traditional stool tests for ova and parasites often miss the diagnosis for a couple of reasons.  One, the stool sample that is actually examined is an exceptionally small bit of the whole that is submitted.  Two, the parasite does not “shed” components in the stool continuously, its life is cyclical; if the stool sample was collected at a time there is no shedding, the diagnosis will be missed.

The only test I’m really familiar with for parasites is the stool for ova and parasite, but I’m going to dabble today a little in discussing Metametrix’s parasite report on the GI Profile 2100.  I’ve seen only one Metametrix test–mine.


Metametrix uses PCR (polymerase chain reaction) to look for parasites and other organisms on its GI Profile 2100.  PCR is accepted to be quite sensitive and specific.  False negatives are possible, but should be rare.  (See here for some false Metametrix negatives when compared to another diagnostic test AND vice versa.  I find this very interesting, and it brings us to the question of quality control, which I’m not going to go into. “6 Gut Infection Case Studies:  Why You Shoud Get Stool Testing Done ASAP” on SCD Lifestyle.) PCR primers can go and attach to microscopically non-detectable fragments from the parasites and their eggs that are in the stool.  It is so sensitive for parasites that it will detect even transient parasitic riders from our environment that will never have a chance to ever take up residence in our bodies.  Metametrix labels this “PPTU” (parasite present, taxonomy unidentified).

You will come in contact with parasites if you garden, eat an apple, eat meat, have a pet, or just live, but only certain parasites have the capability to take up residence in you.  The rest just have to slide on out because they don’t have the anatomy and physiology needed to stay and infect us.  These are the PPTUs.  Metametrix will give a name to organisms known to infect humans so your doctor can treat the parasite, but the PPTUs are ones that almost always should not concern us.  Metametrix has a Protozoan Podcast Transcript which supplies the following information:

“…we identify all of the parasites that are considered problematic for humans and that are tested in standard microbiology labs. That includes parasites such as Blastocystis, Giardia, Cryptosporidium, Strongyloides, and many others…However, because we are using DNA analysis, we can look for additional parasites.  We have a tool, called a universal probe, which looks for parasite DNA–any parasitic DNA–that is present in the patient’s stool.  So if the patient does not have any known human protozoan but is positive for universal protozoan probe, it is listed on the report as “Protozoan Present: Taxonomy Unavailable. When a patient has a PPTU we believe that it is a non-human parasite that is most likely transient and not going to take up residence in the gut, and shouldn’t pose a problem to the patient. It could be a protozoan carried by the patient’s pets or contaminated food that is just passing through. On the other hand, it could be a rare protozoan that is causing symptoms for your patient. In that case it could require assessing other clinical symptoms.

I know some people think Metametrix/Genova is a hoax.  I’ve been sorting out what I think, but only in regards to their 2100 GI Profile.  Honestly, thus far, I don’t think they seem too manipulative or misleading with their GI Profile information.  It sounds like Steve and Jordan of SCD Lifestyle use these kinds of alternative tests a lot.  I like Steve and Jordan because they helped me out once via e-mail, but I wish they didn’t try to sell so many things.  I’m not saying I agree with all they say and do, but I find a lot of good and encouraging information on their site.  Anyhow, here is what they say about these alternative type of lab tests in a post called “Are Unreliable Lab Tests Stealing Your Money?” :

“How to avoid test result betrayalThe best way to avoid wasting money on unreliable test results is to work with a skilled practitioner who knows which lab companies can be trusted right now.  Right now is the keyword there… companies are always changing and we have to be aware of our options when new  and more effective methods of testing come out. In fact, this post could likely be outdated in 6 months.”

Parasite, I Need You:  Parasites Found to be Important in Our Development

Even though I don’t like the thought of wiggly worms laying eggs in my food tube, my recent parasite review was very helpful in my education.  I reviewed significant pathological parasites and their disease states, but I also learned that parasites in the GI tract are probably good for our immune system development, and eradicating them completely may have negative consequences.  Don’t get me wrong, I KNOW and have been tested on pathogenic parasites on numerous exams.  I know there is bad stuff out there, and I would never suggest they not be treated.  But I also know that having unexplainable health problems that don’t respond to anything can make you a little vulnerable to suggestion, including parasite fear, and it helps the brain soothe itself to know that the human body, along time, has come to rely on parasites for healthy development.

A review from Current Opinion in Gastroenterology discusses how inflammatory bowel disease (IBD:  ulcerative colitis and Crohn’s Disease) occurs in countries with good sanitation and food handling practices, but really is not noted at all in lower socioeconomic regions.  It is felt that exposure to helminth infections that used to be ubiquitous in humans helps regulate the intestinal immune system in a positive way, keeping these autoimmune disorders in check.  In fact, there has been success in actually treating IBD with hookworm and porcine whipworm!  They have actually given patients with IBD Trichuris suis, a helminth parasite, and a significant number of them have had remission of their symptoms! (3) They are even looking at helminth treatment in multiple sclerosis! (4)

Doctors Elliott and Weinstock have researched this area and feel that skyrocketing immune disorders in highly-developed, industrialized countries stems from modern hygienic practices eliminating helminths, diseases such as ulcerative colitis, Crohn’s, multiple sclerosis, and asthma.  You can view a section of their writings online:  Helminth Therapy:  Using Worms to Treat Immune-Mediated Disease. (5)

On target, Metametrix steps up and makes this information known.  I went to the Metametrix blog site, and I found this nice, simple piece that presents a fair and biased exploration of parasites,  Parasites, Poop and Public Relations:

“Let’s face it, people do not imagine anything attractive when they think of parasites… DNA-based methods of detecting microbes and helminths are essentially fool-proof in this regard [detecting parasites present in the GI tract], similar to police forensics…There is a growing opinion that early exposure to both harmless microbes found in untreated water and soil and to parasitic worms (helminths) is necessary for proper immunoregulatory pathways to develop in humans.”


I guess in writing this, I wanted to present a moderate view of parasites to help ease the mind of some of those out there searching relentlessly for the cause of their symptoms that have been dismissed by their medical doctors.  I get tired of seeing the fear-tactics employed by many regarding this issue.  I did not have a positive parasite Metametrix test.  If I was symptomatic and I did, I would request treatment from my doctor, unless it was PPTU.  I personally prefer the prescription medicines to the herbals because they are specifically designed to work on parasitic infections, rather than yeasts and bacteria.  I have worked very hard on my bacterial GI microflora through diet and probiotic supplementation, and I don’t want to disrupt that with broader, non-specific anti-microbial agents–prescription, herbal, or otherwise.  I think, if we are not careful, we focus on organisms that could be causing our problems rather than food or environmental issues.  Diarrhea can be caused by FODMAP intolerance.  Proctitis by dairy intolerance.  Headaches by egg sensitivity.  Hormone disruption by plastics and food additives.  And so on.  If you have several issues going on at one time, it can take a lot of time and hard work to sort through it all, and it is enticing to slap the blame and diagnosis on something like parasites or Candida.  However, on the other hand, a minor, sub-clinical parasitic infection could be the last missing piece of the puzzle.  In all of life, usually it is a matter of balance.  A little of this.  A little of that.  Sometimes excessive this.  Sometimes excessive that.  Remove this.  Add that.  For me, I know I had no idea that eggs give me headaches and fatigue and apples and watermelon cause excessive bloating.  Nuts give me a stuffy nose and tension headaches.  I KNOW it’s not all food.  But food plays a huge role in health, healing, and the microbiology of the human body.  Removing common inflammatory foods like grains, dairy, nuts, and eggs went a long way towards helping me feel better.  I wish you much success in your endeavors.  Don’t use anything I write as medical advice.  It is not medical advice.  It is the story and musings of a medical doctor turned stay-at-home mom trying to fix her stomach issues, since her family doctor, gastroenterologist and general surgeon had nothing to add except fiber, Miralax, and senna tea–none of which helped.

If you have a vignette to share about your Metametrix results or an opinion on parasites–go for it!  Leave a comment below to round out the story!  I want to know what you think!  Do we over react?  Do we not?  Too much testing?  Not enough?

All the best,
Posts in the Draft Bin:  More GAPS Intro, What I am Feeding Houseguests While On GAPS


2.  Photo credit:  Wikipedia,

3.  Current Opinion in Gastroenterology:November 2012 – Volume 28 – Issue 6 – p 551–556doi: 10.1097/MOG.0b013e3283572f73

4.  Probiotic helminth administration in relapsing–remitting multiple sclerosis: a phase 1 study, JO Fleming, A Isaak, JE Lee, et al.  Clinical Neurology.  Dec 2010.Published online before print March 3, 2011, doi: 10.1177/1352458511398054 .  Mult Scler.  June 2011.  vol. 17 no. 6 :  743-754


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