This study aims to determine whether the use of two sterile towels for drying after surgical handwashing results in fewer contamination events compared to the use of only one towel among healthcare personnel. This randomized, multicenter, superiority-controlled trial will enroll up to 72 healthcare workers and surgical residents from three hospitals in Bogotá, Colombia. A fluorescent product will simulate bacteria, and contamination will be assessed by evaluating the presence of fluorescent cream after hand drying technique with either two or one surgical sterile towel. Data will be collected through REDCap and deidentified. Differences in the proportion of contamination between the two groups will be assessed using an exact Fischer test, and confounding variables will be included in the analysis through logistic multivariate regression, with a significance level set a priori at 0.05. Results will be submitted for publication in a peer-reviewed journal.

Approval was obtained from the ethics committee of three healthcare institutions. A process of informed consent will be conducted with all participants, and confidentiality and data protection will be guaranteed. A research assistant, unaware of the operational hypotheses and study objectives, will execute the experiment and record the results. There will be no blinding of the intervention for the participants or the assistant. At each institution, randomization will be conducted a priori to determine the operating room where participants should be recruited. Likewise, the intervention to be administered will be randomized. All these data will be stored in opaque envelopes that will be opened at the time of recruitment. A total of 72 participants will be recruited, with 36 exposed to drying with one towel and 36 to drying with two towels. Recruitment will cease upon completion of the respective participants stipulated for each intervention.

The primary outcome of interest will be the presence or absence of contamination. To evaluate this outcome, the gold standard would be the collection of cultures and the analysis of the presence or absence of bacterial contamination. However, due to the costs and methodological difficulties of taking cultures, an indirect method, previously validated as a surrogate, will be employed instead. 2 mL of fluorescent cream (Glo Germ ™) will be applied with a brush proximal to the normally washed area during surgical scrubbing (3 cm above the elbow). Participants will be shown a video on how to dry with one or two surgical towels and will be given one minute to do so. Subsequently, the presence or absence of fluorescent cream on the upper extremities will be evaluated using a UV light lamp. If fluorescence is evidenced in the washed area where it was not applied, it will be considered that there was contamination during the hand drying process.

No interim analyses will be executed. Data will be de-identified for the analysis. Descriptive statistics will be conducted using R studio, and proportions of contamination when drying with one or two towels will be compared. A simple logistic regression will be performed to assess the relationship between the intervention and the proportion of contamination events, and a multivariate logistic regression will be conducted to assess the effect of confounding variables on the outcome. The results will be reported collectively for publication in a peer-reviewed journal.

Inclusion Criteria:

• Workers and students who have a current affiliation with the institutions where the study will be executed.
• Workers and students whose practice or work involves performing surgical handwashing at least once a week for invasive procedures.

Exclusion Criteria:

• Workers and students who do not wish to participate in the study.
• Workers and students whose work activities do not allow them time to participate in the study.
• Workers and students who are allergic to the fluorescent cream
• Workers and students whose nails exceed a length of 0.5 cm from the fingertip edge.
• Workers and students whose nails are painted with polish.
• Workers and students who refuse to remove jewelry and accessories from wrists and hands.
• Workers and students with recent wounds on hands or forearms, including tattoos done in the last month.
• Workers and students who do not adhere to the handwashing and drying technique taught prior to the study's implementation.

Masking will be provided to data analysis expert.