NeuroTalk Support Groups - Skin Punch Biopsy Results

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Skin Punch Biopsy Results

Have folks with confirmed skin biopsy sfn ever seen their results? My neuro was pretty aloof when he reported the results to me as if there was either some damage or their wasn't. When I finally got the results months later, the results are astonishingly low. Showed in the calf I had 2.6 nerve fibers per mm and in the thigh I had 1.6. I think reference value is 5 and 8 respectively. I did this test in April. I wonder if there is any value in retesting to gauge if there is some regeneration or it is about the same. Have others looked at their results and/or done repeat biopsies?

Hey there franklin

My foot/ankle dr actually did my skin punch biopsy. When I went for the results (he uses Bako Pathology Services) he went into all the explanation about their scale before telling me my results. Bako uses 1 thru 15 he said. 15 being the best and usually what a teenager would score. He said 4 to 7 he could work with in trying to regenerate nerves but anything lower he could not.

He then told me my scores.....both punches taken right above the ankle on my right leg.
0.00 Fibers/mm
0.06 Fibers/mm

He said there was nothing that could be done for me and since I was in so much pain I needed to go see a pain mgmt. dr.

The comments on the report say:

The utter absence of fibers following immumohistochemical analysis using anti-PGP 9.5 antibodies is indicative of advanced small fiber neuropathy
Epidermis essentially devoid of fibers

I cried...not because of the results....but because I finally had a dx.

After 3 dr's advised me for over a year to go seek a pain mgmt. dr I did. I've been with him for a year now.

Take care.

Debi from Georgia

St. George-
I thought number for teenagers were unknown? What source did your doc use for these? I got my biopsy at 19 years old and both numbers were normal but still kind of low (like 8-9). Just curious

Quote:

Originally Posted by boiler1993 (Post 1175781)

I have absolutely no idea ..... just advised what he said.

I don't think I've seen anyone else on here that their doctor used Bako Path....did your dr use them ?

Other posters told me early on that they didn't recognize a scale from 1 thru 15 so I really don't know.

Sorry.

Debi from Georgia

Quote:

Originally Posted by franklin76 (Post 1175751)

That is basically how my neuro reacted. (my results are below in my signature). He told me i have SFN but very slight, if at all. I was like so why am I in excruciating pain? They just look at you and start to write the script usually.

There is a point in which you can have repeat biopsies done. It all depends upon what insurance will allow. Usually they don't recommend doing one unless you feel like you are experiencing a lessening of symptoms.

I personally think the skin biopsy is a good test to tell if you have SFN but it doesn't really tell you if the SFN is isolated to certain areas or universal. ALso, the thigh sample is often not as good a specimen as the ankle sample because it has more fatty tissue and is harder to get a good punch of.

I've written about this in numerous other places--

--on this board and others--so just to summarize:

Skin biopsy is repeatable, as it is relatively simple and non-invasive; it's the analysis of the nerve fibers, which involves special staining and electron microscopy, that is complicated (which is why it is done generally only at specialized medical centers). But serial skin biopsies from the same anatomical regions done a year or two apart can provide valuable information about worsening, or improving, small-fiber neuropathy.

The numbers for normal intraepidermal nerve fiber densities were established a few decades ago primarily at Johns Hopkins (the McArthur protocols) on samples of both "normal" and symptomatic" people, but there was wide variation in the numbers among both types and from across anatomical sites (primarily thigh above the knee, calf above the ankle, and upper arm above the elbow). At the time, it was (to me rather arbitrarily) decided to designate those scoring below the fifth percentile and those above the ninety-fifth percentile as having "definite evidence" of small fiber neuropathy. The problem with this in clinical practice is that since most people don't get a skin biopsy until symptomatic, it's hard to know how their results would compare with those they might have had pre-symptoms. For example, someone who might have been in the fourtieth percentile pre-symptoms might show up in the twentieth percentile upon symptom generated biopsy, but would still not technically be diagnosed with definite small fiber neuropathy (though, had this person had a pre-symptomatic baseline biopsy done, the comparative reduction would be suspicious). This is why the condition of the fibers--frayed, swollen, excessively branching--and the trends over time of the density numbers, might make serial biopsies valuable. But, yes, there are cost and insurance considerations.

My biopsy was done at Johns Hopkins and the results do not include numeric values. The ankle site was found to be "devoid of nerve fibers", above the thigh was "reduced with a patchy distribution" and the upper thigh was " segmented and breaking down". Diagnosis was a severe, progressive, length dependent neuropathy. I also have abnormal EMG/NCS that show advanced LFN. Final conclusion was Charcot Marie Tooth (hereditary neuropathy) probable type 2 because of axonal damage.
Once I had a diagnosis there was no interest in further testing and no treatment beyond pain management.