"The contamination level of the stethoscope is substantial after a single physical examination" 1
1 Contamination of Stethoscopes and Physician's Hands After a Physical Examination - Longtin Y., Pittet D.; Mayo Clin Proc. 2014 Mar;89(3):291-9
"The mean rate of stethoscope contamination across 28 studies was 85%" 2
2 The stethoscope and healthcare-associated infection; a snake in the grass or innocent bystander? - O'Flaherty N.; J Hosp Infect. 2015 Sep; 91(1): 1-7.
"Rates of stethoscope and hand hygiene performance were lower than expected in an emergency department setting." 3
3 Observation of stethoscope sanitation practices in an emergency department setting - Vasudevan R., Chowdhury P.; Am J Infect Control 2019 Mar;47(3):234-237.