Laboratory markers in inflammatory bowel disease (IBD) have been studied for various purposes, including diagnosis, monitoring disease activity, predicting relapse, and assessing treatment response. C-reactive protein (CRP) is the most studied marker and has the best overall performance. It is an objective marker of inflammation and correlates well with disease activity in Crohn's disease (CD). However, CRP correlates less well with disease activity in ulcerative colitis (UC) compared to CD. Other markers, such as erythrocyte sedimentation rate (ESR), leucocyte and platelet count, albumin, and α₁ acid glycoprotein, have been studied less extensively or are less useful than CRP. Faecal markers, such as faecal calprotectin, are promising and may be more specific in detecting gut inflammation in IBD patients. Faecal calprotectin has shown good correlation with disease activity in both CD and UC, with better performance in UC than in CD. Laboratory markers are useful in the management of IBD patients but are not magic tools. They should be used as an additive tool to clinical observation and physical examination rather than a replacement. CRP and other laboratory markers should be used in conjunction with clinical assessment to provide a comprehensive understanding of the patient's condition. While CRP is a useful marker in CD, it is less reliable in UC. Faecal calprotectin is a non-invasive, sensitive marker for gut inflammation in both CD and UC. Other acute phase reactants, such as ESR, are less useful in clinical practice due to their longer half-life and interference with other factors. In conclusion, laboratory markers are useful and should be integrated into the overall management of IBD patients. However, no single marker is ideal, and their use should be guided by clinical context and individual patient needs.Laboratory markers in inflammatory bowel disease (IBD) have been studied for various purposes, including diagnosis, monitoring disease activity, predicting relapse, and assessing treatment response. C-reactive protein (CRP) is the most studied marker and has the best overall performance. It is an objective marker of inflammation and correlates well with disease activity in Crohn's disease (CD). However, CRP correlates less well with disease activity in ulcerative colitis (UC) compared to CD. Other markers, such as erythrocyte sedimentation rate (ESR), leucocyte and platelet count, albumin, and α₁ acid glycoprotein, have been studied less extensively or are less useful than CRP. Faecal markers, such as faecal calprotectin, are promising and may be more specific in detecting gut inflammation in IBD patients. Faecal calprotectin has shown good correlation with disease activity in both CD and UC, with better performance in UC than in CD. Laboratory markers are useful in the management of IBD patients but are not magic tools. They should be used as an additive tool to clinical observation and physical examination rather than a replacement. CRP and other laboratory markers should be used in conjunction with clinical assessment to provide a comprehensive understanding of the patient's condition. While CRP is a useful marker in CD, it is less reliable in UC. Faecal calprotectin is a non-invasive, sensitive marker for gut inflammation in both CD and UC. Other acute phase reactants, such as ESR, are less useful in clinical practice due to their longer half-life and interference with other factors. In conclusion, laboratory markers are useful and should be integrated into the overall management of IBD patients. However, no single marker is ideal, and their use should be guided by clinical context and individual patient needs.