A LOOK INSIDE THE LAB

Behind the curtain: What really happens to your Cologuard Plus® box after you send it back

How can poop predict cancer? It’s quite the story! Advanced technology, specialized lab technicians, and multiple quality checks all work together to turn your sample into a result you can trust.
Exact Sciences Corporation | October 2026
Lab worker in a white coat loading sample containers into laboratory equipment.

Key takeaways

  • Every Cologuard Plus sample goes through multiple quality checks before a result is reported.
  • Machines help process samples, but trained laboratory professionals oversee every step.
  • Samples are tracked throughout the process using barcodes, so your sample is always connected to your info.
  • Most samples can be processed successfully without any issues.
  • The Cologuard laboratory operates around the clock to help deliver timely results.

So, you get your Cologuard Plus test kit. You follow all the instructions: deposit your sample, fill out the labels, seal the box, and ship it back to our lab.

Then what? We’ll show you.

So take your seat, silence your phone, and settle in to learn exactly what happens to your sample at our lab, and how your poop is the star of the show.


Start with Cologuard

From your bathroom to our lab

Once you ship back your Cologuard Plus kit, it travels to a specialized laboratory that operates 24/7 to ensure an efficient testing process.

Have no fear, nothing you send us will be spread on a slide and analyzed under a microscope. And we certainly never judge the color or consistency of your ‘deposit.’ But we do use some pretty cool machines — plus a whole lot of research and highly-trained human technicians — to analyze your ‘sample.’

Act I: The meet-cute

Let us set the scene: We open on a blue and white box that has just arrived at the lab.

The first priority is making sure your box gets checked in and your patient information is verified.

Digital technology reads the barcodes and handwritten labels, and matches information quickly. But don’t worry, actual human lab techs will review anything that needs a closer look, like if your handwriting is a little on the creative side.

Once verified, your sample is never anonymous throughout the testing process. Multiple checks help ensure your sample stays connected to your information everywhere it goes.

Technology helps process the sample. People help ensure the process stays accurate.

Act II: Getting to know your sample

Now that we know whose stuff is in which box, we examine it and prepare it for analysis.

First up, we make sure your ‘contribution’ meets all the requirements for testing.

Now you might be thinking, “Requirements?? I didn’t know there were requirements. What if my specimen isn’t good enough?”

But let me stop you right there. The vast majority of samples move through this process successfully. And our lab teams are experienced working with all kinds of poop. Yours is probably fine. And if it isn’t, we’ll just send you a new kit. Think of it like a call back. Actors love those.

After it’s approved for testing, your sample is mixed by robots (the good kind!) to help ensure consistency, and then portions of that mixture are prepared for the different tests that come next.

The star of the show is now ready for its close-up.

Act III: Your sample is put to the ultimate test(s)

It’s finally the big moment. Your sample’s time to show what it’s really made of — literally.

See, every day, your colon naturally sheds cells into your poop. Those cells contain DNA that can provide important information about your colon health.

The Cologuard Plus test looks for two important clues:

  • Altered DNA that may be associated with colorectal cancer or precancer
  • Blood in the stool that may also be a warning sign

By looking for both altered DNA and blood, the Cologuard Plus test gathers information that can help identify signs of colorectal cancer and certain precancerous growths.

So, back in the lab, specialized technology helps scientists analyze your sample. The testing process isolates DNA from your bathroom waste (genius!) and prepares it for analysis. Sophisticated instruments then look for specific DNA markers associated with colorectal cancer and precancer.

A separate test looks for blood in the stool sample, which could also be a sign of colon cancer.

And while, a lot of the testing process is automated — picture a montage of spinning centrifuges, blinking lights, and tiny test tubes — there are real, highly trained people involved throughout the workflow. Lab professionals monitor instruments, review quality measures, and step in whenever a manual review is needed.

Act IV: The analysis

Next, an FDA-approved algorithm takes your sample’s combined molecular and hemoglobin results and determines your risk level. Or, in plain English: Our trusted testing process determines if there are signs of colon cancer and precancer in your poop.

Act V: The result

The whole process wraps up when we send the test results to you and your healthcare provider.

If your test is negative, it’s a happy ending. You’re good to go for the next three years, then you can rescreen with the Cologuard Plus test.

Now if your test turns out positive, that does not mean you have cancer. It just means there’s a sequel to this story. ‘Part Two’ would be getting a follow-up colonoscopy, so your doctor can determine next steps.

Q & A with the cast: We answer your questions about the Cologuard Plus testing process

Now that you know how the Cologuard Plus testing process works, you might have some other questions. Ask away!

How does the lab make sure samples don’t get mixed up?

That's one of the most common questions people have about Cologuard. Our lab uses barcode tracking and digital systems to monitor samples throughout the testing process. Every sample is assigned identifying information that follows it from arrival through result generation. Multiple checkpoints help confirm that samples remain associated with the correct patient information.

Do people ever send back something besides poop?

Short answer: Yes, and please don’t do that.

Longer answer: Yes, in addition to viable samples, we have received some very sweet cards and notes from our patients (which we love!).

What if my sample can’t be tested?

This situation is uncommon, but it can happen. Our lab uses several quality checks throughout testing. Internal controls help confirm that the sample contains enough human DNA for analysis and that the testing process worked properly.

If a sample can’t be processed or doesn’t meet testing requirements, you may be asked to collect a new sample. Not the end of the world.

Curtain call

Well, that was a dramatic ride! Over five acts, your ‘star performer’ went through multiple tests, a lot of soul-searching, and in the end got a result you can trust.

From collecting your sample at home, to shipping, check in, and analysis — every sample is handled and tested by trained lab professionals and sophisticated technology.

So, if you’re age 45 or older and at average risk for colon cancer, your Cologuard Plus story awaits.

Safe.
Noninvasive.
FDA-approved.