stool sample

Q: 34 years old male with known history of HIV is admitted to ICU with severe diarrhea. Ideally, stool sample should be sent to laboratory within? (select one)

A) 30 minutes

B) 60 minutes

C) 6 hours

D) 24 hours

Answer: A

To have the best yield from a stool sample, two basic principles should be followed:

• not be refrigerated
• ideally must be received by the lab within 30 minutes

A warm and fresh stool maximizes the chances of detecting trophozoites. Trophozoites are considered the active, infective form of protozoa. The stool should be preserved in Cary-Blair media in small community hospitals where 24/7 lab services are unavailable.

#GI

References:

1. Jones J, Reinke SN, Ali A, Palmer DJ, Christophersen CT. Fecal sample collection methods and time of day impact microbiome composition and short chain fatty acid concentrations. Sci Rep. 2021 Jul 7;11(1):13964. doi: 10.1038/s41598-021-93031-z. PMID: 34234185; PMCID: PMC8263620.

2. Abrahamson M, Hooker E, Ajami NJ, Petrosino JF, Orwoll ES. Successful collection of stool samples for microbiome analyses from a large community-based population of elderly men. Contemp Clin Trials Commun. 2017 Sep;7:158-162. doi: 10.1016/j.conctc.2017.07.002. Epub 2017 Jul 6. PMID: 29250605; PMCID: PMC5726580.

3. Wasfy M, Oyofo B, Elgindy A, Churilla A. Comparison of preservation media for storage of stool samples. J Clin Microbiol 1995; 33:2176.