Fecal Calprotectin Results: What 50, 150, 250, and 500+ Can Mean

If you have just received a fecal calprotectin result, the first thing you probably did was type the number into a search bar. A value like 150, 250, or 500 lands with no context, and the lab report rarely explains what it means for you specifically. A calprotectin levels chart can give you a rough map of the common result bands, but the honest answer to "what does my number mean" depends heavily on your history, how the sample was collected, and whether the value is rising or falling over time. This guide walks through the ranges people search for most and what each can, and cannot, tell you.

What a normal fecal calprotectin range looks like

Calprotectin is a protein released mainly by neutrophils, a type of white blood cell. When the intestinal lining is inflamed, neutrophils migrate into the gut wall and shed calprotectin into stool, so higher stool levels generally track with more intestinal inflammation. The most widely adopted cutoff for a normal fecal calprotectin range in adults is under 50 µg/g, though the same review notes that some primary care pathways use under 100 µg/g and that different laboratory assays can produce 2- to 3-fold differences for the same stool sample. That last point matters: a "normal" number is defined partly by which test your lab runs. There is no single universal threshold, which is one reason a chart should be read as a set of probabilities rather than a verdict.

Reading a calprotectin levels chart: the common result bands

The bands below reflect thresholds used in major guidelines and studies. They are a starting point for a conversation with your gastroenterologist, not a diagnosis.

Result (µg/g)	What it commonly suggests
Under 50	Typically within normal limits; also used as a stricter target after treatment
50 to 150	Usually low enough to help rule out active inflammation in someone in remission
150 to 250	Borderline or indeterminate; repeating the test is often advised
250 to 500	Elevated; active inflammation is likely and warrants assessment
Over 500	Substantially elevated; strongly associated with active disease

For someone in symptomatic remission with previously confirmed disease, AGA guidelines say a fecal calprotectin under 150 µg/g can help rule out active inflammation and support continued monitoring rather than an immediate change in treatment. The AGA Crohn's disease biomarker guideline applies the same 150 µg/g cutoff, and uses a lower threshold of under 50 µg/g to avoid routine endoscopy in asymptomatic patients within a year of surgery.

What 150 and 250 can mean

If you searched "what does calprotectin 150 mean," the answer sits on a boundary. Values in the 150 to 250 range are frequently treated as indeterminate. A primary care faecal calprotectin pathway classifies 100 to 250 µg/g as borderline and recommends repeating the test while checking for confounders such as recent NSAID use. Above roughly 250 µg/g, the picture shifts. In a large ulcerative colitis trial analysis, a fecal calprotectin at or below 250 µg/g corresponded to minimal to no endoscopic inflammation, which means values climbing past that point make active endoscopic inflammation more likely. The same primary care pathway triggers referral to gastroenterology once a result exceeds 250 µg/g. For someone searching "calprotectin 250 Crohn's," a number in that zone is a reasonable prompt for endoscopic assessment rather than a guess at medication changes.

Is 500 high, and what a flare-level number looks like

A result over 500 µg/g is well above every remission threshold, so the short answer to "is calprotectin 500 high" is yes. Higher calprotectin values tend to correspond with greater disease activity: one study reported that fecal calprotectin correlated positively with clinical activity scores in both ulcerative colitis and Crohn's disease, with patients whose endoscopic scores were higher consistently showing elevated levels. A single high number does not confirm a flare on its own, because symptoms, endoscopy, and other biomarkers all factor into that judgment. What calprotectin level means a flare depends on your personal baseline. A jump from 60 to 400 may be more meaningful for you than a stable reading of 300 in someone who consistently runs high.

Why the same number can mean different things

Several factors can push a result up without reflecting a true change in your disease. The Clinical Chemistry review found that NSAIDs can raise fecal calprotectin to as much as 520 µg/g and proton pump inhibitors up to about 150 µg/g, and that age, obesity, and gastrointestinal bleeding also influence values. Collection timing matters too. A prospective study in active ulcerative colitis measured a median coefficient of variation of 52% between stool samples collected within a single day, with levels rising the longer the interval between bowel movements, leading the authors to recommend sampling the first morning stool for consistency. This variability is exactly why one isolated number can be misleading.

Why the trend matters more than any single value

Because of assay differences, day-to-day variation, and confounders, a single reading is a snapshot rather than a trend line. The most useful signal comes from serial measurements taken the same way over time. The Clinical Chemistry review reported that patients with fecal calprotectin repeatedly above the study cutoff had a 53% to 83% probability of relapsing within the next two to three months, and it stressed using the same assay for monitoring because of the 2- to 3-fold spread between tests. Guidelines increasingly favor this approach: ACG guidance supports using fecal calprotectin to assess treatment response, evaluate suspected relapse, and monitor during maintenance rather than as a one-time verdict. A number tracked across several tests, alongside your symptoms, tells your gastroenterologist far more than any single result can. If you have one value in hand, the most productive next step is to note it, keep the report, and ask how it compares to your history.