What not to do with bloody poo...

After arguing that Geriatrics really is a worthy subspecialty, I recount all of the poop I just can’t get away from… even after the patient is technically dead… Then prepare to be bombarded by the mounting evidence against and festering frustration with fecal occult blood tests being used just for funzies.

Lee MW, Pourmorady JS, Laine L. Use of Fecal Occult Blood Testing as a Diagnostic Tool for Clinical Indications: A Systematic Review and Meta-Analysis. Am J Gastroenterol. 2020 May;115(5):662-670. 

Bhatti U, Jansson-Knodell C, Saito A, Han A, Krajicek E, Han Y, Imperiale TF, Fayad N. Not FIT for Use: Fecal Immunochemical Testing in the Inpatient and Emergency Settings. Am J Med. 2022 Jan;135(1):76-81.

Román-Colón D, Rodriguez-Ramos R, Cerra-Franco J, De Jesús-De La Cruz H, Mirza ZT, Cepero-Jimenez C, Ramos-Marquez R, Martinez-Souss J, Toro DH. The Use of the Fecal Immunochemical Test in the Acute-Care Hospital Setting. P R Health Sci J. 2025 Dec;44(4):189-194.

Transcript

SPEAKER_00 0:19

Howdy howdy friends and comrades. It's time for episode five. I work at Best Boise Hospital, and I work there because it is the best hospital in Boise, so aptly named. And I loved my job. One of the amazing things about being in geriatrics is just how much of a team approach it is. In post-acute care, occupational therapy, physical therapy, rec therapy, RNs, nurse aids, admin coordinators, housekeeping, social work, restorative programs, psychology, MDs, and APPs, we are all essential to the excellent, patient-centered, holistic care provided to our patients. Sometimes the most important care provided of the day is the activity that rec therapy did with everyone in the afternoon. Sometimes one of our housekeepers notices a patient decompensating before nursing staff does. I like to think that we are as much equals as we can possibly be, and that we should all be able to go out and have a beer together after work. Except that I don't drink beer. In the evening it's usually hot water with Murillax, but you get my point. I mention all of this because of some buzz I've been hearing a little bit lately. Not a roar, just a tiny rumble, and that is the underplaying of the value of geriatricians and geriatrics' care more generally. The collective group of us in post-acute care provide a very carefully tailored, high level of care to older adults. And it really drives me nuts when people say that older adults are just older adults. That is not true in the same way that children are not just short adults with bad manners. Not everyone can do what we are specifically trained to do. So next time you have a delirious old woman with the strength of 10 men trying to choke out a nurse in the middle of the night, or a 75-year-old primary care patient with insulin-dependent diabetes, hef ref, COPD, cirrhosis, osteoporosis, gait instability, alcohol use disorder, and likely dementia, who can't remember to take his meds and has just one low-functioning friend who only buys him beer, and you're like, Fall a geriatrician, and we will know what to do. If you don't think it's a subspecialty, you must acknowledge it is at minimum a superpower. But I digress because today I'm going to talk about poop, which is an all-ages problem. Or maybe a privilege, if you will, because when you can't go, it's a big deal. I'm sort of working my way through the body excretions week to week. Today, crap. It stinks, it's messy, and people do weird things with it. I would have completely missed out on this knowledge had I not gone into healthcare. When people are altered in any way and they feel something cold and squishy on their butt, their lizard brain says, that's uncomfortable, get it away. During my brief stint as a hospitalist, I had a patient who came in on just about every synthetic illicit drug you've heard of and a few that possibly haven't even been invented yet. He was like the walking dead with all cortical activity on mute. Eyes open, moving around, nobody home. He appeared to be eating a high-fiber diet because he just kept putting out these big soft turds. Enviable if you're trying to avoid hemorrhoids. And then he would grab them out of his underwear and fling them across the room with really no awareness of what he was doing. His floor was covered in poop, and none of us would go in there. Not even housekeeping or nursing staff, because he couldn't follow directions and no one wanted to be a target. By the end of the day, he had sobered up and was begging me not to tell his girlfriend why his room smelled so bad when she came to visit. And smearing one's poop on the walls is a thing. It's not like one guy did it one time, it's like many people are doing it at some point in their delirium or if they're psychotic. I get if you are sick or intoxicated and you're just covered in your own poop, that happens a lot. But that extra step of coloring the walls with it is like a pathology that needs a DSM-5 diagnosis. Poop smearing. Like hoarding. I was going to say but grosser, but that's maybe a toss-up because often hoarding involves poop in some way and more dead things and flies. Demented people often poop in the trash can because it looks like a toilet. So I respect that they're making an effort. I've only ever had one patient poop in the trash can and then take a bite of it. No, he did not eat soft dog food for dinner. He was delirious, I guess. It didn't happen again. We consulted psychiatry. They had nothing to offer except a breath mint. And the pies de resistance of poop came when I was a third-year medicine resident on a busy ICU service at one of my training hospitals. Senioring Mickey was the biggest test of medical prowess and grit of my residency tenure. I loved that rotation as an intern, and it is such an intense and inspiring rotation that I think everyone at least fleetingly considers being an intensivist during their month on that service. But part of what made it such a rich experience was the incredible attendings we worked with. Esteemed pillars of the Palm Crit Care Universe, respected educators, and legendary thinkers and researchers, you get the picture. And this was where everyone from the five-state area was flown to when no other hospital could handle it. So needless to say, no matter how nice and welcoming the attendings and fellows were, the service could be a little intimidating. I wasn't so much intimidated by the medicine. That part was exhilarating and I was eager to really suck the marrow out of every case I had. What scared me to death was that as senior resident, I was the code leader in the ICU. And I don't think I had to run a single code through my whole residency leading up to that rotation. And the critical care codes are a zoo. There will be at least like 20 people there, and a line of people out the door waiting to take their turn at CPR all eager, and the ICU nurses are all older than me and have been working there for like 20 years. Even the janitor has more experience than the third-year resident. So when it was my day to hold the pager every fourth day, I was always super nervous. So the days are trickling by, and I'm practicing great medicine, and we're saving lives left and right, and my intern is spectacular, and I just love working with her, and we're having fun together and supporting each other through patient deaths, but I'm ready for it. And I'm keeping my bladder very empty. And then at some point, it happens. There is a code blue, and it is my day with the pager. It's in the other wing in the neurocritical care unit, so my intern and I take off down the hall, and I've got my ACLS cheat cards in hand, and I get to the patient room, and sure enough, there are a swarm of people already around the door, and I was there like only about 30 seconds after the code blue was called. The code team is very eager. And the first thing I notice is this very seasoned, amazing, smart, legendary book writing even crit care doc who has started the code. And when I come in, instead of continuing to lead the code as I had hoped he would do, he yields to me. And I'm like, okay, I got this. You got this. And then, instead of leaving the room, he goes over to the monitor and stands there and stares at me. I am immediately completely flustered. And everyone is watching me, and I start to sweat. And chest compressions are going, and I remember introducing myself as a code leader and asking for a summary of events and where we are time-wise and the compressions. And then another crit care doc, also legendary, but someone I didn't actually particularly care for because, well, I thought he was kind of a jerk. Watson and stands beside the other legendary but nice crit care doc, and now they are both staring at me. And then it's time for a pulse and rhythm check, and I can't see because someone is standing in front of the damn monitor blocking my line of sight. So I'm trying to look around this person and trying to ask them to move, but there is a lot of chatter happening and he can't hear what I'm saying. And so crit care doc number two tells me the rhythm and there's no pulse. So I say, resume chest compressions, and I'm thinking, oh my god, he probably doesn't know that I can't see the monitor and now thinks I'm a complete idiot. That was back when I used to care what people thought of me. I don't miss those days. So I'm sweating more, and the guy is still standing in my line of sight, so I step over slightly to tell him to move, and someone yells, stay at your post. I don't know who, but that person is a jackass. So I jump back and I know we have two minutes until the next rhythm pulse check, and I remember that we're supposed to give epinephrine, so I ask for that, or pharmacy reminded me maybe, and we did it, I don't know. But now I'm sweating more and my mascara is running into my eyes. And my eyes start to water, and my vision is a tiny bit blurry. And I get someone else to have the guy move, but then I realize the monitor is far enough away that with my eyes watering, I can't really see the screen. And I start to panic. And just before I'm about to ask them to move it closer, I smell something horrible. And look at the patient, and as they are doing chest compressions, deep brownish-green liquidy diarrhea has started to shoot out from underneath the hospital gown and onto the bed. And it's not like a trickle, like waves of it shooting out. And nursing staff is calling for chuck pads and towels, and diarrhea is just going everywhere. More and more, squishing out with every compression. Hundred compressions a minute. Squish, squish, squish, squish. And the folks who have their hands on the femoral pulses are just dutifully standing there as they are getting bathed in poo. And a few folks start dry heaving, probably med students, and everyone is getting sprayed a little. Pretty sure I got some in my hair. And then finally it's time for a rhythm and pulse check, and thank the Lord, baby Jesus, that patient has a pulse. So then we're doing post-arrest care and we're checking vitals and getting fluids going, and it's over. And the patient got ROSC after only two rounds of CPR, thank goodness. And the nursing and housekeeping staff really had their work cut out for them. But what I will say about the whole experience is that the only good thing was that when we all debriefed later, no one really remembered how I screwed up because diarrhea wins every time.

Intro to fecal occult blood testing

SPEAKER_00 10:03

The reason I started with a bunch of crappy stories today is that we are going to talk about the crappiest of the crappy uses for the two most common medical crap tests. That is, using FIT or Guayax dual testing to work up suspected GI bleed. Let's first discuss appropriate uses. The fecal immunchemical test, or fit, was specifically designed and tested for colorectal cancer screening in asymptomatic average risk patients. So, no one with family history or IBD or other risk factors, and no one with anemia, weight loss, blood coming out of their butt, or some other sign or symptom that might lead you to believe they have colon cancer. Why? Because the fit wasn't validated in these settings, and so we wouldn't know what to make of the results. Instead, with increased risk or with signs or symptoms, you must immediately go to colonoscopy, which is why my GI friends have a lot bigger houses than I do. The fit has a very narrow purpose. This could be the point where I just drop the mic and we all go home, but I worry I haven't convinced you yet, so I'll continue with the episode. FIT completely replaced the prior Guayak-based fecal occult test as the stool colorectal cancer screening test of choice. The older test was sort of a disaster for a number of reasons I won't completely go into right now, but the required three different collections and dietary and medication restrictions for a few days before the collections were onerous to say the least, and reflective of just how finicky a test it is in the first place. Keep in mind it's only 50 to 75% sensitive for cancer. Lots of false positives and lots of false negatives because of things completely unrelated to blood. But don't feel bad for the guyak. It went on to find new life in urgent cares and emergency departments everywhere, where it was literally used in the workup of GI bleeds, sore throats, and migraine headaches. Okay, just the first one of those, but the last two make just about as much sense. The FIT test works differently than guyak and has a number of advantages for cancer screening. First, because it detects globin, which is digested in the small intestine, it is less likely to detect upper GI bleeding, which, when screening for colorectal cancer, is important. To be fair, sometimes all the heme might be digested in the GI tract as well, making the guyak negative for an upper lesion. FIT doesn't require any dietary modifications, and only one test is needed annually. It is at least 75% sensitive, but because it misses some cancers, you need to do it on a regular schedule. In the US, that's yearly, in some other countries, every two to three years. Unfortunately, this test has also been hijacked for purposes it was not designed for. Like I said, FIT is validated only for screening for colorectal cancer in asymptomatic average risk patients in the outpatient setting. The sensitivity and specificity of it for this purpose, derived from many, many screening trials, has validated its use in this circumstance. It is very specifically not a test for blood in the GI tract. It may miss blood in the GI tract. It was purposefully designed to miss blood from the upper GI tract. It may detect some blood, but what is the relevance of that? I don't know. I guess I would think it would detect blood that is briskly pouring out of the esophagus and stomach and exceeding the digestive capacity of the small intestine. And I guess it would detect blood that is copiously coating every turd that slips out. But in those two cases, couldn't you just do a finger swipe to discover the obvious?

Test characteristics of FOBT for chronic GI bleed, or not

SPEAKER_00 13:34

For cheaper? Well, no one listens to rational argument anymore, and so there have had to be papers published on this subject that using guyak and fit to help diagnose suspected GI bleed is at a minimum unhelpful and at worst wasteful and misleading. So what are the test characteristics for Guayac and Fit in these alternative situations? Why do we even care about test characteristics? Well, they help with clinical decision making. A sensitive test should allow us to catch most to nearly all cases of a particular condition so we know if it's reasonable to keep that in our differential diagnosis. Another way of thinking about it is that a sensitive test lets us know it's okay to rule out a diagnosis without fear that we're missing it. A D-dimer is a very sensitive test that we often use to rule out a blood clot, because almost no one with a value less than 500 will have one. So we can be reassured that there is no clot if it's low. A test that is specific means it is specific to your diagnosis in question and won't be positive in other diagnoses. It can be used as a confirmatory test. A D-dimer is not a very specific test for blood clots because it can be elevated in some other situations, so you have to do a confirmatory test, which is a more specific test, usually a CTPA. So a test that is sensitive and specific lets us say it definitely might be diagnosis X and is unlikely to be diagnosis Y. But there aren't many tests like that. You often have to sacrifice one for the other. Oh my god, that was a lot of nerding out. At some point we'll talk about positive and negative predictive values, which are related to sensitivity and specificity, but that's all I can handle for now. Like I have stated, to the point that you probably all want to throw up at this point, the test characteristics quoted for fit and guaiak apply only to testing average-risk asymptomatic patients for colon cancer in the ambulatory setting. The best attempt to generate test characteristics for guyak and fit use in alternative situations was a systematic review and meta-analysis by Lee et al. published in the American Journal of Gastroenterology in 2019. The situation of interest for our purposes was anemia, although they did study a few other conditions. They specifically excluded studies with patients with overt bleeding, that is, witnessed or found on physical exam, and thus ultra high probability of a GI bleed. We'll save that scenario for later because, yes, some providers still order FIT tests when someone has blood pouring out of their butt. They found 22 studies, 12 of which were investigating anemia of unknown cause, seven with guy, and five with fit. The final diagnosis was determined by scope, so the gold standard. And this was a valiant attempt to determine the sensitivity and specificity of the stool test for some kind of GI lesion in the setting of anemia, but all of the studies suffered from selection bias. They were samples of convenience, and there's absolutely no way to know if their results would be at all generalizable. They did give us some compelling results though. The sensitivity of guiact testing for any cause of bleeding was 58%. So not great, because you were going to miss pathology in 42% of patients with a lesion. With fit, it was 64% sensitive for any cause of bleeding, meaning you'd miss 36% of lesions. Both were about 80% specific for a lesion, meaning that you could have a fair amount of false positives leading to unnecessary scopes as well, but overall less false positives than false negatives. So basically what they were saying is that if you use Guayaquil Fit to guide whether you need a scope in iron deficiency anemia, you are going to miss one-third to one-half of patients with actual pathology and do an unnecessary procedure 20% of the time. Well done, you.

The disaster that FOBT use in acute GI bleed

SPEAKER_00 17:10

But like I said, none of these studies were looking for an acute GI bleed. And that is the situation that annoys me the most because whipping out the poop test just seems like a waste of resources. Two papers have come out in the past few years that addressed this situation with fit specifically and complement one another quite nicely. The first paper is from Botti et al. Not Fit for Use, Fecal Immunochemical Testing in the Inpatient and Emergency Settings, published in the American Journal of Medicine in 2022. This was a single-center retrospective observational study, so a fancy way of saying a chart review, at one hospital. They stated in the abstract that their purpose primarily was to investigate the effect of fit testing on clinical decision making, but they didn't do a stellar job of describing or prioritizing their outcomes. They looked at a lot of different things and didn't correct for multiple statistical tests, so this was really just a descriptive study, but that serves our purposes just fine. They included any adult with a fit test completed in the ED or inpatient setting across a two-year period. There were 550 fit tests found for 550 unique patients. 45.3% were completed in the ED and the rest on the inpatient unit. Reasons for the fit? Well, three were for colorectal cancer screening, but let me point out that fit is validated in an ambulatory setting, not an acutely ill population, but whatever, good effort. 44% were ordered for anemia, 41% for a suspected acute GI bleed. And what really concerns me is that in half of these patients the cause was thought to be upper. Remember that whole digestion of hemoglobin and the small intestine thing I mentioned earlier? Anyway, what's even stranger is that in about three-quarters of the suspected GI bleeders, it was witnessed overt GI bleeding. At that point, ordering a test is like walking outside to look at the thermometer to see if it's hot out. Almost half of patients who were fit tested were positive. Those who were fit positive definitely got a scope more than those who were fit negative, 33% versus 7%. But when they looked at other factors in multivariate analysis, fit results were not associated with odds of having an inpatient endoscopy. At least at this hospital it wasn't. But here's the interesting part. Only a little over half of folks who were FIT positive and had a scope had a bleeding source identified. So they had false positives. And in those who were FIT negative but underwent scope, half had a possible bleeding source documented. So false negatives. Now it's hard to know how to generalize these results since it's one hospital and local practices and patient populations can vary quite a bit, but they would seem to suggest that fit testing, even for acute GI bleeding, inevitably leads to false positives and false negatives. And having a fit test didn't seem to affect whether a person got a scope or not anyway, because the gastroenterologists relied on a better standard. That is, good judgment, and probably a finger up the ass. The next paper lets us drill down into some of the details. The use of fecal immunochemical tests in the acute care hospital setting by Roman Cologne et al. and published in the Puerto Rican Health Science Journal in 2025. This was a similar single-center retrospective chart review of patients with a fit test ordered in the ED or inpatient setting over a three-year period. It was conducted at a VA in San Juan, Puerto Rico. It was also mostly another descriptive study. Here, there were 1,354 patients with a FIT result. It was basically all men with a mean age of 73, typical VA population. The other study didn't really elaborate on demographics except to say that a quarter were under age 45. So the two studies definitely had different patient populations. I think then that the concordance of the results of the two papers suggests that their findings are reasonably generalizable in general. In this study, 63% of tests were completed in the ED, the rest inpatient. 46% of FIT tests were performed in the presence of overt GI bleeding. 43% of FIT tests overall were positive, but less than half of these had a scope. 12% of those who were FIT negative went on to have a scope. So it doesn't seem like FIT results had a big impact on whether patients were scoped or not here either. The interesting part in this study was that they outlined how many patients had positive or negative FIT results for various signs and symptoms. Okay, first, the rectal exam was just not done in 40% of patients. Shame, shame. But you know, maybe the patients declined. If red blood was found, the fit was negative in only a few cases, but it was negative in a few cases. And if dark blood was found, which I'm presuming meant melana, it was negative in a full 20% of cases. Similarly, in patients who came in complaining of rectal bleeding, fit was negative in 24% of cases. And for those complaining of dark or black stools, it was negative in 53% of cases. Alright, so with the subjective complaint, we can't verify that the patient actually had what he said he had. And maybe his black stools were just from iron or peptobismol or black licorice gatorade. I don't think that's a thing. In which case it should be negative. But when we look at patients with positive findings on colonoscopy, not EGD, the globin should not have been digested. All the blood should still be there. Fit was negative in 11%. And we just only have the numbers for patients who actually had a scope. Okay, so poop tests bad. But where does all of this leave us regarding how to determine if our patient has an acute GI bleed? Well, none of the GI organizations have any published guidance or guidelines about this subject. I think it is just too rudimentary for them to bother. They are too busy bathing in money and laughing at us generalist peasants. So I'll tell you what I do. You can't go wrong with the old finger up the butt trick. Check the rectal vault for blood. I have heard some old school docs claim that lube might make it difficult to tell what you swipe out, but I prefer not to damage the therapeutic relationship. If your finger fails, you check a CBC and trend. You should probably do that anyway. If it's completely stable, they probably don't have a particularly concerning bleed, if there is one at all, and they can get a scope at a leisurely pace. That is, outpatient. If it's dropping and they're hypotensive, well, you can probably see it coming out at that point. Though not always. At that point they need a scope, not a smear on a card or swab. So glad you tuned in again this week, even though my show was super crappy. Now I'm going to go and relax with some hot water and Miralax. See you next time. Thank you.