Purpose: The adverse association of sarcopenia with post-operative outcomes has been reported. There is no preferred screening tool to identify sarcopenia among this patient group. The aim of this pilot study was to assess the validity of two well-known questionnaires on patients with sarcopenia. Methodology: The study included 30 subjects who underwent cardiac surgery at Townsville University Hospital from July 2023 to January 2024. Patients were assessed pre-operatively based on the Revised European Working Group of Sarcopenia in Older People 2 (EWGSOP) for sarcopenia which defines from a combination of Muscle function (MF) and Muscle Mass (MM). Accordingly, MF was assessed with handgrip strength and 5-time chair rise tests. MM was defined according to our cut-off lowest sex-specific quartile of Pectoralis Major area from a cohort of 237 patients undergoing cardiac surgery. Sarc-F (strength, assisting with walking, rising from a chair, climbing stairs, and falling) and Sarc-CalF (SARC and calf circumference) were compared. The diagnostic precision of both methods was determined using the receiver-operating characteristic (ROC) curves and area under the ROC curves (AUC). Results: Sarcopenia was identified in 10 (33%) of patients. Comparing the two screening questionnaires, AUC curves of SARC-F was 0.890 (95% confidence interval (CI), 0.75-0.99) and mildly higher than Sarc-Calf AUC of 0.855 (95% CI, 0.69-0.99) (P>0.05). The sensitivity of SarC-Calf to diagnose Sarcopenia was significantly higher compared to SarC-F (70.0% (CI,40.0-89.2) vs 60.0% (CI, 31.1-83.2) (P<0.05). Conclusion: SarC-F performance in detecting sarcopenic patients by only assessing muscle function was satisfactory but not sensitive. Addition of calf circumference to SarC-F as SarC-Calf, provided a more sensitive screening test for sarcopenia in patients undergoing cardiac surgery. This has implications in the incorporation of muscle morphometry in the objective assessment of sarcopenia.