目的：化脓性脑膜炎病原学检出率较低，尤其脑脊液改变不典型时给临床诊断带来困难。已证实血降钙素原(PCT)测定对鉴别细菌与病毒感染有重要价值，但在化脓性脑膜炎与病毒性脑膜炎的鉴别诊断方面与CRP、血沉比较孰优孰劣未见报道,另外诊断化脓性脑膜炎时PCT临界值的确定也未见报道。该文通过血PCT测定并与CRP、血沉比较探讨其对儿童化脓性脑膜炎与病毒性脑膜炎的鉴别诊断意义。方法：用免疫荧光法测定了41例急性脑膜炎患儿血PCT(其中化脓性脑膜炎18例，病毒性脑膜炎23例),同时测定血CRP、血沉。结果：化脓性脑膜炎组PCT，CRP及血沉分别为51.73±30.75μg/L，182.36±54.5mg/L和50.44±8.95mm/h；明显高于病毒性脑膜炎组0.84±0.99μg/L，8.90±10.66mg/L和16.75±13.23mm/h(P<0.01)，受试者工作特征曲线下面积PCT为0.984(95%可信区间0.953～1.013)，而CRP为0.983(95%可信区间0.954～1.012)，二者比较差异无显著性(P>0.05)。有2例病毒性脑膜炎PCT值高于0.5μg/L，而化脓性脑膜炎病人均高于此值。结论：血PCT同CRP在儿童化脓性脑膜炎与病毒性脑膜炎的鉴别诊断方面有重要参考价值，优于血沉。

OBJECTIVE: To investigate the ability of serum procalcitonin(PCT) to differentiate between bacterial and viral meningitis. METHODS: The serum PCT levels were measured in 41 children with acute bacterial (n=18) or viral (n=23) meningitis by immunoluminometric assay. Meanwhile serum CRP levels and erythrocyte sedimentation rate (ESR) were measured. RESULTS: The children with acute bacterial meningitis had higher levels of PCT (51.73±30.75 μg/L) and CRP(182.36±54.5 mg/L)and ESR (50.44±8.95 mm/h) than those with viral meningitis (0.84±0.99 μg/L, 8.90±10.66 mg/L and 16.75±13.23 mm/h respectively,P<0.01). Both PCT and CRP had high predictive value for bacterial meningitis based on the area under curve of the receiver operating characteristics curves, 0.984 for PCT (95% confidence interval 0.953-1.013) and 0.983 for CRP (95% confidence interval 0.954-1.012)(P >0.05). All of the children with bacterial meningitis had serum PCT levels above 0.5 μg/L, but only 2 patients with viral meningitis exceeded this value. CONCLUSIONS: The measurement of serum PCT levels may be of value in the differential diagnosis of meningitis due to either bacterial or viruses.