<![CDATA[Motorcycle workshop mechanics work in environments where vehicle exhaust may accumulate, particularly in workshops located near dense traffic and with limited ventilation. Carbon monoxide (CO) is not directly measured in this study; therefore, daily working hours and years of employment are used as occupational indicators of possible long-term exposure. This descriptive cross-sectional study analyzed serum creatinine levels among 30 motorcycle workshop mechanics on Jalan Riau, Pekanbaru. Respondents were selected by purposive sampling based on predefined eligibility criteria. Venous blood was collected, processed into serum, and analyzed using an Optiva photometer with a Glory Diagnostics enzymatic creatinine kit at 510 nm. Descriptive statistics were used to summarize creatinine distribution by age, daily working duration, and length of employment. The results showed that 17 respondents (56.67%) had serum creatinine levels above the reference range (>1.3 mg/dL), while 13 respondents (43.33%) had normal levels (0.7-1.3 mg/dL). Increased creatinine levels were more frequent among mechanics working 12 hours/day (75%) than among those working 8 hours/day (20%), and were also more common in respondents aged 30 years or older and those with more than 10 years of employment. These findings suggest that mechanics with longer occupational contact in CO-prone workshop environments may have a higher proportion of elevated serum creatinine. However, because ambient CO or carboxyhemoglobin was not measured, the results should be interpreted as an occupational-health screening finding rather than evidence of direct causality. Improved ventilation, routine health monitoring, and occupational safety education are recommended.]]>
