BackgroundIn clinal practice, differentiating glioblastoma (GBM), brain metastases (BM) and primary central nervous system lymphoma (PCNSL) preoperatively is difficult and directly affects the therapy of patients. This study was to evaluate the diagnostic value of routine blood biomarkers in patients with GBM, BM and PCNSL, and find a preoperative differential diagnostic tool for the three brain tumors.MethodsThe perioperative medical records of 70 GBMs, 41 PCNSLs and 81 BMs and their preoperative blood test results were compared and analyzed. A diagnosis model was founded for differentiating GBM, BM and PCNSL.ResultsPatient age, plateletcrit (PCT), international normalized ratio (INR) and thrombin time (TT) were found independently associated with differentiating diagnosis of the three brain tumors analyzed by multinomial logistic regression. Compared with GBM patients, BM patients tend to be elder (OR=1.055, 95% CI 1.016-1.094, p=0.005) and have lower PCT level (OR=0.008, 95% CI 0.004-0.017, p=0.027). Besides, GBM patients own lower INR and higher TT when compared with PCNSL patients and BM patients. We build an efficient diagnostic model with these parameters and diagnosis accuracies of this model were 88.2% and 76.1% in BM and GBM, respectively. ConclusionsThe preoperative PCT, INR and TT may be used as inexpensive blood diagnostic biomarkers for differentiating patients with brain metastases from other intracranial malignant tumors.