Background <p>Warfarin remains a key oral anticoagulant in many healthcare settings, requiring regular international normalized ratio (INR) monitoring to ensure therapeutic safety and efficacy. The Time in Therapeutic Range (TTR) is the conventional metric for assessing anticoagulation quality, but its fixed thresholds may underestimate control in patients with near-target INR values.</p> Objective <p>To compare TTR with the Expanded Time in Therapeutic Range (ETTR), which incorporates INR values within ± 0.2 units of the target range, in a pharmacist-managed anticoagulation clinic in Malaysia.</p> Methods <p>This retrospective study included 176 patients receiving warfarin therapy at a pharmacist-managed anticoagulation clinic. TTR and ETTR were calculated for each patient, and the proportions achieving anticoagulation control were compared. Net reclassification improvement (NRI) analysis was performed to assess the incremental value of ETTR over TTR.</p> Results <p>A greater proportion of patients were classified as having adequate anticoagulation control using ETTR compared to TTR, with no instances of downward reclassification. The NRI was + 0.242 (<i>p</i> &lt; 0.001), indicating that ETTR identified a substantial number of patients as adequately controlled without misclassification.</p> Conclusions <p>ETTR captured more patients with clinically acceptable INR control than TTR, without compromising classification accuracy. These findings support ETTR as a complementary quality indicator to TTR, particularly for evaluating real-world warfarin management in pharmacist-led anticoagulation services.</p>