Nowadays, a reliable method for reconstructive surgery is flap surgery. With its help, the body is able to mend almost any damage to its vascularized tissues. The current study set out to determine whether measuring flap blood glucose was a sensitive and dependable predictor for venous congestion early detection. Methods: Thirteen male Sprague-Dawley rats (n=26) were divided into two groups for the purpose of this experiment: one group received vertical rectus abdominis muscle flaps with upper pedicles while the other group did not. One group received venous occlusion of the pedicle, and the other group received no such treatment (Control group). We measured the interstitial glucose in the flaps every ten minutes and checked the rats' glycemia in the caudal vein of their foot at regular ten-minute intervals from the start to the finish of the experiment. Results: At 0 minutes, 20 minutes, and 30 minutes, the flap glucose level showed a statistically significant decrease compared to the foot glucose level (p=0.01, p=0.005, p=0.002 respectively). At 10 minutes, 40 minutes, 50 minutes, and 1 hour, the flap glucose level showed a high statistically significant decrease compared to the 10 minute foot glucose level (p-value < 0.001). The mean flap glucose level in the cases group decreased significantly (p-value < 0.001) compared to the mean foot glucose level (mean = 228.1 ± 65.1, range = 114.7 - 342.1), as compared to the mean foot glucose level (mean = 179.7 ± 54.3, range = 89.7 - 297.2). With an AUC of 0.7 and a p-value of 0.054, the ROC curve demonstrated that the mean glucose level could discriminate between the flap glucose level and the foot glucose level in the cases group at a cutoff level of 187.2, with a sensitivity of 69.2%, specificity of 69.2%, PPV of 69.2%, and NPV of 69.2%. Conclusion: The potential for non-invasive and cost-effective early management in cases of venous congestion in tissue flaps has been suggested by monitoring blood glucose levels.