Transdermal microfluidics systems for diabetes management have gained increasing attention and emerged as a potential hope. Traditionally, a hypodermic needle was utilised for biofluid sampling and subcutaneous insulin delivery. However, this invasive technique causes undesirable pain and tissue trauma. Other than blood, interstitial fluid contains a high concentration of glucose compared to another body fluid, e.g., saliva and tears. The interstitial fluid can achieve high sensitivity and accuracy in measuring glucose for non-invasive glucose sensor development. Due to minimal or non-invasive performance (less pain), microneedles are widely discovered to replace the hypodermic needle, and their combination with the microfluidic system is expected to improve diabetes treatment management. Herein, the comparison of the glucose concentration before, during, and after insulin (injection) between interstitial fluid and blood of the live diabetic rats using both microneedles and hypodermic needles was investigated. Based on findings, the changes in glucose concentration over time of interstitial fluid compared to a blood sample show a similar trend. Furthermore, microneedle is one of the most effective methods to extract interstitial fluid for continuous blood glucose monitoring.