Severe belly pain, a high fever, blood in the stool, or signs of dehydration such as dizziness on standing and passing very little urine need emergency care now. Call 911 or your local emergency number.
Most cases begin with a disruption of the dense bacterial community that normally lives in the colon. That community resists colonization by outsiders, and when it is thinned out, dormant spores can germinate and release toxins that injure the lining of the bowel 1. The everyday triggers sit upstream of that biology.
Recent use of some medicines is the trigger most adults encounter. Research suggests that recent exposure to some medicines is the strongest single risk factor for this infection 2. If you think something you take is involved, ask your prescriber rather than stopping it on your own.
Age and setting matter too. Older adults, people who have recently spent time in a hospital or care facility, and people with weakened immune systems carry more risk than the general adult population 3. Cases also occur in people with no recent hospital contact at all, which is part of why the illness is now described as a worldwide problem rather than a purely hospital one 4.
Spread is the other half of the story. Spores are shed in stool, survive on surfaces and hands for long periods, and can be picked up by another person, which is why hand washing with soap and water and careful cleaning are emphasized around anyone with symptoms 5. Some people carry the organism without any symptoms at all, and carriage is not the same thing as illness 5.
It helps to know what the illness tends to look like. The usual picture is frequent loose to watery stools, often three or more unformed stools in a day, with lower abdominal cramping, a feeling of urgency, loss of appetite and sometimes fever 6. Mucus can appear in the stool, and visible blood is less typical and is a reason to seek care promptly. Appearance alone cannot confirm what is behind a bout of diarrhea, because many other things produce the same look.
Before assuming the worst, remember how ordinary most loose stools are. A change in diet, a heavy night of alcohol, a lot of coffee, travel, a short viral stomach bug, food that disagreed with you, high stress or a sudden jump in training load all loosen stools for a day or two. None of those is a lab finding. What separates them from something that needs testing is duration, fever, severe pain, blood and signs of fluid loss.
Blood tests cannot find this bacterium, so they are not how the infection is identified. A stool sample is the test that matters, checked for the toxin the organism produces and, in many labs, for the gene that allows it to make that toxin, with results read alongside the person's symptoms 7. Blood markers answer a different question. They describe how much inflammation is present, how well the kidneys are holding up against fluid loss, and how hard the illness is hitting overall.
| Marker | Why it is linked to this symptom | What a result can and cannot tell you |
|---|---|---|
| Total WBCs | White cells rise when the lining of the colon is inflamed and the immune system is responding to an infection | A raised count flags inflammation or infection somewhere in the body. It cannot name the organism, and it does not separate a gut infection from a chest or urinary one |
| Creatinine | Watery stool pulls large volumes of fluid out of the body, which reduces blood flow through the kidneys and lets creatinine climb | A rise can reflect dehydration or kidney strain and is one of the values clinicians watch during a severe bout. Muscle mass, meat intake and hard training also move it |
| Albumin | Albumin falls when inflammation is active and when protein leaks through an inflamed bowel wall | A low value is a clue to how much strain the body is under. It cannot confirm a cause, and liver function, nutrition and fluid status all affect it |
Typical lab reference ranges for these three markers look like this.
| Marker | Typical lab reference range | Units |
|---|---|---|
| Total WBCs | 4.0 to 11.0 | x10^9/L (about 4,000 to 11,000 cells per cubic millimetre) |
| Creatinine | 0.6 to 1.1 (women), 0.7 to 1.3 (men) | mg/dL |
| Albumin | 3.5 to 5.0 | g/dL |
These are typical lab reference ranges, not diagnostic verdicts. They vary by lab, age and sex, so always read a result against the range printed on your own report.
A high white cell count means the immune system is responding to something, and an inflamed colon is one of the things that can drive it. Clinical guidelines regard a white cell count at or above 15,000 cells per cubic millimetre as one of the criteria that marks a more severe episode 7. A marked rise in white cells alongside watery diarrhea is a well-recognized part of the clinical picture 6.
The observation is useful. The meaning is limited. A raised count says inflammation, not location. A chest infection, a urinary infection, a skin infection, a dental abscess and plenty of non-infectious inflammation all raise white cells. Counts also shift with acute physical stress, with smoking, with a very hard training session in the hours before a draw, and with some medicines, which is one more reason to ask your prescriber what you are taking before reading anything into a single value.
The next step is the practical part. A white cell count that sits above the standard range in someone with ongoing diarrhea is worth discussing with a clinician promptly, because it changes how urgently the stool test and the rest of the assessment are handled. A normal count does not rule the infection out. Plenty of people with a confirmed infection have counts inside the standard range, and the stool test remains the thing that settles the question.
If you want the background on what this marker measures and what else moves it, the Total WBCs page covers it.
Creatinine rises during heavy fluid loss because the kidneys receive less blood, so they clear less of it. Creatinine is a waste product of normal muscle metabolism that the kidneys filter out at a fairly steady rate. When several days of watery stool drain the body's fluid, blood volume drops, filtration slows and the level in blood climbs. That is why a rising creatinine is one of the values clinicians track during a bout of this infection, and guidelines regard a serum creatinine above 1.5 mg/dL as one of the markers of a more severe episode 7. Kidney involvement is one of the features used to sort milder episodes from those that need closer monitoring 9.
Plenty of other things move creatinine, which is why the number is read in context. A larger muscle mass produces more of it, so a heavily muscled adult can sit near the top of the range while perfectly healthy. A big meat meal the day before a draw nudges it up. So does an intense training block, simple under-drinking, and some medicines. Age and sex shift the expected range as well, which is why the reference interval printed on a report differs between people.
The next step with a creatinine that has moved upward during an illness is straightforward. It is worth discussing with a clinician promptly, especially when it comes with dizziness on standing, very little urine, a dry mouth or confusion, because those together point to significant fluid loss rather than a lab quirk. A repeat test once you are well again tells you far more than the single value taken mid-illness. The Creatinine page explains what the marker measures and how it is interpreted.
Albumin can fall during a gut illness because inflammation reduces how much of it the liver makes and an inflamed bowel wall lets protein leak out. Albumin is the most abundant protein in blood. It holds fluid inside the blood vessels and carries hormones, calcium and other molecules around the body. During an acute inflammatory illness the liver shifts production toward other proteins, and albumin drifts down over days rather than hours.
Reviews of the illness describe low albumin alongside raised white cells and raised creatinine as part of the pattern seen in more serious episodes 10.
Albumin is not a specific marker, and that is the honest limit. It falls in liver disease, in kidney conditions that let protein escape into urine, in poor nutrition and in chronic inflammation of any kind. It can also look falsely high in a dehydrated person, because the same amount of protein sits in less fluid. A single low albumin in someone who is acutely unwell says the body is under strain. It does not name the strain.
What to do with it is simple enough. A low albumin during an illness is worth repeating once the acute phase has passed, and a value that stays below the standard range afterwards is worth discussing with a clinician, since the reason then lies somewhere other than the recent bug. The Albumin page sets out the detail.
A completely normal blood panel can sit alongside an active infection, so a clean set of results never rules this out. Blood work measures the response, not the organism. The organism is found in stool, and the decision about whether a positive stool result reflects true infection or simple carriage depends on the person's symptoms as much as the lab report, which is one of the recognized difficulties in diagnosing this condition 8.
Several things no blood test will show. A previous episode that has quietly returned is one of them, and recurrence after an episode is a well-described feature of this infection 9. Carriage without illness is another, since some people shed spores while feeling entirely well 5. Ordinary causes of loose stools sit in the same blind spot. A food that does not agree with you, a change in fibre intake, a short viral bug, travel, heavy alcohol use, high stress and a long-standing pattern of cramping and urgency all produce symptoms that a standard panel reads as normal.
Timing matters too. Markers drawn on the first day of an illness may not have moved yet, and markers drawn in the middle of it can exaggerate how things stand, because dehydration concentrates the blood. A result read in isolation, without the symptom timeline next to it, is the most common way a panel misleads.
This is why the sequence runs symptom first, stool test second, blood markers alongside. The blood work supports the assessment. It does not replace it.
Seek emergency care now for severe or worsening abdominal pain, a swollen or rigid belly, a high fever, blood in the stool, repeated vomiting, or signs of significant dehydration such as dizziness on standing, confusion, a racing heart or passing very little urine. Those signs need urgent assessment, not a wait-and-see approach. Call 911 or your local emergency number.
Arrange a prompt appointment, rather than an emergency visit, for diarrhea that has lasted more than a couple of days without improving, diarrhea that starts after a recent hospital or care-facility stay, diarrhea that follows recent use of some medicines, or diarrhea in an older adult or anyone with a weakened immune system. Those situations are the ones where a stool test is most often appropriate, and a clinician decides whether to order it 7.
Do not try to settle this yourself, and do not stop or change anything you have been prescribed without speaking to your prescriber first. Treatment decisions belong to a licensed provider, who weighs the test result, the symptoms and the rest of your history together.
If you are having thoughts of self-harm, call or text 988 (US) or your local emergency number now.
The three markers on this page are standard blood tests, and the FitScript Essential panel measures white cells, creatinine and albumin in one draw alongside the rest of a baseline workup. Membership covers 150+ biomarkers tested per year, so these values can be tracked over time rather than read once in the middle of an illness, which is usually the least informative moment to interpret them.
Atlas, the AI health advisor, explains what each result means in plain language and shows how it sits against the standard reference range and against your own previous draws. Any next step, including whether a stool test or any other assessment is appropriate, is decided by a licensed clinician after reviewing you. This page is educational and is not medical advice. Discuss your results and any proposed next step with a clinician or licensed provider.
For a look at a different pattern of cramping, urgency and stool changes that is not an infection, see the overview of ibs symptoms.
Clostridium difficile, now usually written Clostridioides difficile, is a spore-forming bacterium that can overgrow in the colon when the normal gut bacteria are disrupted. It produces toxins that irritate the bowel lining and cause watery diarrhea, cramping and fever. A stool sample identifies it, and a clinician decides what happens next.
Stool is typically loose to watery rather than formed, passed frequently, often three or more unformed stools in a single day. Mucus may be visible and the odour is often described as unusually strong. Visible blood is less typical and needs prompt care. Appearance alone cannot confirm the cause, so a stool test is what settles it.
Yes. Spores are shed in stool and can survive on hands, bathroom surfaces and shared equipment, so another person can pick them up and swallow them. Washing hands with soap and running water and cleaning bathroom surfaces thoroughly both reduce spread. Alcohol gel alone is less effective against spores than soap and water.
Through a stool sample, not a blood test. The lab checks the sample for the toxin the bacterium makes and, in many labs, for the gene that lets it make that toxin. A clinician reads the lab result together with your symptoms, because a positive sample in someone with no symptoms means something different.
No. Blood tests do not find the bacterium anywhere. What they show is how the body is responding, including white cell count for inflammation, creatinine for fluid loss and kidney strain, and albumin for overall strain. Those values help a clinician judge severity while the stool test answers the identification question.
Risk is higher in older adults, in people who have recently spent time in a hospital or care facility, in people with a weakened immune system, and after recent use of some medicines. Ask your prescriber about anything you take. Cases do also occur in adults with none of these risk factors.
Do not stop anything on your own. Some medicines can disrupt gut bacteria, but stopping a prescribed one without advice can create a bigger problem than the one you are solving. Tell your prescriber what you are taking and what symptoms you have, and let them decide whether anything should change.
Yes, symptoms can return after an episode appears to have settled. Watch for the same pattern of frequent watery stools, cramping and fever coming back within weeks of recovering. Contact your clinician if that happens rather than waiting it out, because a repeat assessment and a repeat stool test may be appropriate.