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My dog has bloody diarrhea, negative parvo test. Can it be wrong?

Updated On September 23rd, 2025

Pet's info: Cat | Domestic Shorthair | Male | neutered | 1 month and 28 days old

4 days ago I brought him to the vet as he'd bloody diarrhea & vomiting. The vet made a medical guess saying he had parvo virus. The following two days're him being healthy again without any blood excretions & vomiting. He played actively & eating well. Today, I returned to the vet for testing. His stool sample's tested to be negative. After returning home, his condition came back worse all the sudden.He vomited & had bloody stool more than before. Doesnt eat. Can the test be wrong? What do I do?

3 Answers

Most Helpful Answer

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Answered By Jeffrey Milner

Veterinarian

Published on October 29th, 2017

Parvo tests, just like many other medical tests, are not 100% accurate, There are certain strains of the Parvovirus that will show up as negative 100% of the time. You must rely on the veterinarian's clinical experience with the disease and the dog's presentation to determine if Parvo is an appropriate diagnosis. Sounds like Blue should get some radiographs and blood work to see what else might be going on. Hope this makes sense.

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    Answered By Dr. Strydom, DVM

    Veterinarian

    Published on July 17th, 2021

    Even if the parvo test was negative, parvo is most likely. The test is not 100% accurate. She should hospitalized and treated as such. She cannot continue this way. I suggest you take her back to your vet for hospitalization and supportive care - intravenous fluids, antibiotics, anti-emetics, etc. If blood testing has not been done that should be done as well. If her white blood cell count is negative then it’s definitely parvo.

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    Answered By David Elbeze, DVM, MRCVS

    Veterinarian

    Published on March 23rd, 2018

    Even if the second bar appears slightly, it is an indication that the test is positive and your puppy probably has parvo. blood in the diarrhea doesn't always occur and in many cases it does not appear in the first few days of the disease.

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