No Fingers Allowed


Sent from a reader …

Because stool obviously transmogrifies as it exits the rectum.

Stool contained on the end of one’s finger after performing a rectal exam and then transferred to a hemoccult card causes hemoccult cards to give wrong readings and therefore the results “may not be accurate.”

However, stool that is plopped in the toilet, mixed with water, possibly urine, and whatever else is growing in the toilet bowl … no problemo. Definitely accurate.

This “results may not be accurate” disclaimer is reportedly added to every stool sample the hospital reports because the hemoccult card manufacturer said that the cards are only to be used for “formed stool”. Not sure how the lab tests to determine whether the sample is “formed” or is “diarrhea,” but I’m not a lab technician. Perhaps they test the moisture content of the sample prior to actually applying the requisite number of drops of hemoccult developer.

The hospital also reportedly had an entire committee meeting where multiple educated professionals and administrators thought it was appropriate to include the “results may not be accurate” disclaimer given the manufacturer’s guidelines.

That then begs the question that if the stool results “may not be accurate,” then why is the hospital reporting on the results at all?

I’m sure that a fear of liability for not following the manufacturer guidelines in using the product had nothing to do with the committee decision, either.


  1. It’s more about the lab not being able to prove where the stool came from or the condition of the stool. When I was a CLA, I had the fun task of prepping the wbc stool slides – any pre-made slide that came in got tagged with a comment such as that. (This was a CAP/CMS procedure, iirc)

    Call the lab floor (not the rep or client services) and ask, we were always happy to educate doctors and nurses about what we did behind the magic curtain of a reference lab.

    • I wasn’t aware that there was a law/rule/regulation requiring that labs prove where samples come from or the condition of the sample before issuing a report. Is that a JCAHO requirement? CLIA requirement?
      Why doesn’t the lab add a disclaimer that blood values may not be accurate unless we can prove that they are from a vein. Never know if the blood may have been scooped up from someone’s menses or their surgical wound. Oh, and what if it was from an arterial source instead?
      If urine comes from a urostomy versus a Foley versus the good ol’ urethra, does it affect the reporting or results? Do labs issue a similar disclaimer?
      If every lab is required to verify the validity and source of each specimen it runs, then this is even more bass ackward than I thought it was.

      • Hrm. Food for thought. I know I was told that CAP required it during one of our inspections. And I just realized that the image was sent in by a reader. Curses. I’ll still stand by the calling of the lab directly to clear up automated comments like that.

  2. If someone bleeds easily (low platelets, blood thinners) trauma from a dre can cause bleeding in the rectum, which would result in a positive OB that doesn’t signify actual GI bleeding.

    • First of all, I’d like to see any scientific data substantiating your position.
      Technically, you’re right, but I’m calling BS. If someone bleeds easily, the stool – which is not lubricated and which is a heck of a lot wider than a doctor’s finger – is going to cause the same bleeding.
      If a patient has some type of diathesis, then the doctor can use his/her clinical judgment in determining whether the sample is a false positive. If labs are going to warn us about every potential false positive/false negative, then the reports for every single lab test are going to have to be pages long.
      Maybe lawyers can start suing labs because they don’t warn doctors about every possibility that causes false positives and false negatives in every single lab result.

      Second, if your reasoning is why this disclaimer is present, it is a case of the exception swallowing the rule.
      Imagine if every aspect of our lives was governed by the theory that “in rare instances it could happen, therefore we should warn against it and not trust it under every circumstance”.
      “Traffic lights may not work correctly. Green light may or may not be accurate.”
      “Turn signals may not be accurate. Hand signals recommended.”
      “Medications may not be accurate due to mechanized bottling. Frequent random chemical assays recommended to ensure proper medication and dosage.”

      • I had a patient with new leukemia. Platelets were 16, hgb was like 6. She had a rectal exam, which of course resulted in a positive OB. She was thus admitted for a GI bleed. Her new leukemia was overlooked until someone finally requested a hematology consult 2 days later. While I seriously question this practitioner’s abilities missing that diagnosis anyways, the truth of the matter is that with low platelets a DRE will cause bleeding. Often times these patients do require laxatives so that they won’t have bleeding with bowel movements. And yes, a finger is harder and sharper than stool. We don’t do rectal temperatures, exams, or medications in people with platelets under 50 for this reason.

        I do agree, however, that many laboratory tests can have false positives and negatives, so why do they single this one out?

      • I’m not sure what a leukemic patient with GI bleeding has to do with false positive hemoccult results.
        The “truth of the matter” is that you cannot cite one source to substantiate your assertion that DREs are more likely than stool to cause bleeding in patients with low platelet counts. You assert facts where none exist.
        Your assertion that “fingers are harder and sharper than stool” is also wrong, but since most readers of this blog have both fingers and pass stool, I’ll let them judge the veracity of your statement.
        You still haven’t answered the questions posed above.

  3. I once worked at a hospital where I had to “prove” every year that I was able to interpret reading the stool occult blood card and pH paper. When I worked day shift, I also had to prove that i could color in between the lines.

  4. I read this comment thread with great interest. I’m just a lawyer, but it just so happens that my wife is a clinical laboratory scientist at a renowned local hospital, with a degree in medical technology. Before that, she was a training specialist for a company that manufactured hemoccult cards.

    I sent her the post because I thought she’d find it interesting. This is what she says:

    “Fingers can rip the anus making it bleed so then you don’t really know if the positive blood result is from that or an actual internal bleed. The disclaimer is necessary because lab staff doesn’t collect the sample and we do not know how they obtained it. There are special kits available to properly collect the sample. Docs never want to attend continuing ed sessions for POC lab testing but they always mess it up. If the lab had it our own way, we’d dicontinue all POC testing. All accurate test results begin with a quality sample.”

    From my perspective, I have to call BS on WhiteCoat’s reply to Christine. Having had the experience of both a digital rectal exam and a bowel movement, anecdotally it isn’t hard to imagine that the DRE is way more likely to cause a tear than a big brown toilet trout is.

    So it seems like the disclaimer is there to tell the physician “if you didn’t do the test right (and experience tells us you often don’t) the results may not be right, so don’t blame us.” This seems not litigation-driven, but designed to ensure that the clinician gets an accurate result, or if they know the sample was rectally collected, to tell them that they should be aware of the increased potential for a false positive.

    Don’t get me wrong, I am sure there are instances where liability-driven disclaimers exist. This doesn’t look like one though. I think because WC has a hammer, the disclaimer looks like a nail to him.

    • Once again, we have someone who knows little or anything about the clinical practice of medicine who is opining on the merits of … the clinical practice of medicine.

      “I am a clinical lab scientist and had a rectal exam once, therefore I have conclusive knowledge about how doctors perform rectal exams.” Based on my extensive experience watching Dr. Edward Scissorhands and his progeny perform rectal exams, it is my opinion that patients are lucky they don’t need post-rectal exam abdominoperineal resections.

      Rectal exams *could* cause bleeding. Labs want to *ensure* that clinicians get accurate results. Does your masters degree having wife possess any evidence that rectal exams *do* cause rectal bleeding more than bowel movements in her renowned hospital files? Any scientific evidence how these policies *ensure* proper clinical results? Studies maybe? Percentages of cases? Perhaps she has published a paper on the topic. Any scientific evidence at all, counselor? Do you think your wife would get past a Daubert hearing on the topic with her qualifications?
      And why doesn’t your wife’s clinical laboratory publish disclaimers about all the conditions that may affect a laboratory sodium value? Or doesn’t your wife’s renowned hospital think that “ensuring” clinicians get accurate sodium results is important?

      Come to think of it, I flew on an airplane once and I watch flight patterns on all the time. Perhaps I should contact the FAA to give them my opinions about air traffic control.

      I’m glad that your wife and all of the clinical laboratory scientists think it is medically essential to verify the source of these samples before running them.

      After all, for all we know the samples could be brain biopsies from the people who create these policies.

  5. Stool occult blood is a useless test in the ED anyway. We shouldn’t be doing it ever, unless you are screening for colon cancer, the only thing it is validated for, and if that’s what you are using it for you are probably doing it wrong anyway.

  6. I just couldn’t resist commenting. White Coat, you are so spot on. Is it not ludicrous to do a test the results of which “may not be accurate”?

    We don’t need the lab to tell us that the test may not be accurate. We all know that stool for occult blood can give both false positive and false negative results. But being doctors, we factor in that knowledge with the clinical situation.

    I am proud to say that having recently passed the hospital’s inservice, I have been credentialed to perform fecal hemoccult tests without supervision. Hence, the lab is no longer in the loop.

    • I’m not aware of any data for hemoccult testing in any setting other then colorectal cancer screening. So, who knows?

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