Rinsing the mouth prior to expectoration

Q: Rinsing the mouth prior to expectoration improves the quality of the sputum?

A) True

B) False

Answer: A

The yield of the sputum Gram stain correlates directly with the quality of sputum submitted to the lab, particularly in community-acquired pneumonia (CAP). In contrast, sputum Gram stain does not help much in atypical pneumonia. This is due to the fact that patients with atypical pneumonia have a lot of mucoid sputum, and large Polymorphonuclear neutrophils (PMNs) but a few organisms. 

The diagnosis yield of sputum can be increased by a few measures such as:

• Obtaining the sputum prior to antibiotic administration
• Rinsing mouth prior to obtaining sample
• NPO an hour or two prior to expectoration
• Prompt inoculation of the culture media 
•  Rapid transport to the lab

#lab-medicine

#ID

#pulmonary

References:

1. Moncayo-Nieto OL, Reid P, Laurenson IF, Simpson AJ. Improving the use of sputum cultures in lower respiratory tract infection. J R Coll Physicians Edinb. 2013;43(2):108-13. doi: 10.4997/JRCPE.2013.204. PMID: 23734350.

2. Cartuliares MB, Skjøt-Arkil H, Rosenvinge FS, Mogensen CB, Skovsted TA, Pedersen AK. Effectiveness of expiratory technique and induced sputum in obtaining good quality sputum from patients acutely hospitalized with suspected lower respiratory tract infection: a statistical analysis plan for a randomized controlled trial. Trials. 2021 Oct 2;22(1):675. doi: 10.1186/s13063-021-05639-1. PMID: 34600559; PMCID: PMC8487344.