From the paper:
“For many tests, this association became gradually weaker at earlier time points. However, 8 years before a diagnosis of CD, levels of leukocytes, neutrophils, and platelets remained significantly higher in CD cases compared to controls. 7 years before CD diagnosis, levels of CRP were also higher, while levels of hemoglobin were lower. 5 years before CD diagnosis, levels of monocytes were higher in cases than controls, while levels of iron, albumin, and bilirubin were lower. In UC, we also observed significant differences in several blood tests in the pre-diagnostic phase of disease, although these differences were detectable over a much shorter period compared to CD. For example, 3 years before UC diagnosis, cases had higher levels of CRP, leukocytes, neutrophils, eosinophils, and platelets compared to controls, but these differences were not apparent at earlier time points (Figure 1). In total, 14/17 and 9/17 tests showed pre-clinical changes (within time interval −2 to −9) that were associated with CD and UC, respectively (Figure 1).”
https://dx.doi.org/10.1016/j.xcrm.2023.101263
I’ve had blood tests done, and they didn’t catch my colitis until I had it. It took months to get it under control.