Background: The WHO defined ‘diabetes mellitus’ (DM) as a metabolic disorder characterised by chronic hyperglycaemia with disturbances of carbohydrate, fat and protein metabolism resulting from the defect in insulin secretion, or inaction, or both. When not identified early and controlled, acute and chronic life-threatening consequences may result. Identifying DM early for treatment and management, as well as clinically monitoring recovery and improvement during treatment, involves the assessments of biomarkers. The types, choice, sensitivity and descriptive information trends of these biomarkers are very important. Aim: Some prognostic biomarkers and parameters that this review identified include glycated haemoglobin, white blood cells, mean neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, total leukocytes and neutrophils, plasma low-density lipoprotein, high-density lipoprotein and very low-density lipoprotein, platelet, fibrinogen, D-dimer and C-reactive proteins. Results: These parameters display increases in DM, while red blood cell, haemoglobin concentration, activated partial thromboplastin time, prothrombin time and partial thromboplastin time are decreased. Conclusion: With sound knowledge of the variations of these markers and parameters, observed reversal during treatment and management of DM and its complications can be better monitored, and guided decisions can be made.