How long can a stool sample stay good before pathology?

Stool samples should be kept cool and sent for processing as soon as possible. The exact time frame for how long a stool sample can stay viable for pathology testing depends on various factors, including the specific test being performed and the method of sample collection and storage.

Here is a general guideline for how long stool samples can stay good under different conditions:

1. Refrigerated (2-8°C): Stool samples stored in a refrigerator can typically remain viable for up to 7 days for most routine tests, such as stool culture, ova and parasite (O&P) exam, and occult blood testing.

2. Ambient Temperature: Stool samples left at ambient temperature (room temperature) may become unusable for many tests within a few hours due to rapid bacterial and enzymatic degradation.

3. Formalin-Preserved Samples: Stool samples preserved in 10% neutral buffered formalin can remain stable for longer periods, up to a few weeks or months, and can be used for certain tests, such as microscopic examination for parasites or ova.

4. Frozen Samples: Stool samples collected and immediately stored at -20°C or lower can be viable for several months or longer, allowing for more extended storage and testing times.

It's important to follow specific collection and storage guidelines provided by the laboratory or healthcare provider when submitting stool samples for pathology. Delaying sample processing or mishandling can affect the accuracy and reliability of test results.