Study On The Diagnostic Value Of The Ratio Of Lactate Dehydrogenase To Adenosine Deaminase In Pleural Effusion For Tuberculous Pleural Effusion

[Objective]To evaluate the diagnostic value of pleural effusion(PE)lactate dehydrogenase(LDH)to adenosine deaminase(ADA)ratio(pLDH/pADA)for tuberculous pleural effusion(TPE),and hope to provide new ideas for the early diagnosis of TPE.[Methods]Retrospective analysis was performed on 412 patients with PE who first visited the department of respiratory and critical care medicine of our hospital from June 2017 to May 2020.On the basis of the pathogeny,the patients were divided into 179 cases of TPE group,67 cases of pneumonia pleural effusion(PPE)group and 166 cases of malignant pleural effusion(MPE)group.IBM SPSS21.0 software was used to perform statistical processing of the obtained data.The medical records of the above cases could be for analysis,including baseline information and the results of hematological indexes and pleural effusion indexes.A receiver operating characteristic(ROC)curve was constructed for obtaining cut-off value of the pLDH/pADA and area under the curve(AUC).The sensitivity(SEN),the specificity(SPE),the positive likehood ratio(PLR)and the negative likehood ratio(NLR)was calculated to evaluate the diagnostic and differential diagnosis efficacy of pLDH/pADA for TPE.[Results]The mean values of pLDH,pADA and pLDH/pADA in the TPE group and the MPE group were 441.80U/L vs 555.29U/L(P=0.218),50.21U/L vs 12.61U/L(P<0.001)and 9.23 vs 45.51(P<0.001).These were 441.80U/L vs 1036.88U/L(P=0.012),50.21U/L vs 25.39U/L(P<0.001)and 9.23 vs 35.40(P=0.048)in the TPE group and the PPE group and were 555.29U/L vs 1036.88U/L(P=0.012),12.61U/L vs 25.39U/L(P<0.001)and 45.51 vs 35.40(P<0.001)in the MPE group and PPE group.Using the pLDH/pADA as the diagnostic index of TPE,the area under the ROC curve was 0.962(95%confidence interval:0.9460.979,P<0.01),and the best cut-off value was 15.04.When pLDH/pADA≤15.04,the SEN,SPE,PLR,NLR and Youden index are as follows:91.00%,90.00%,9.10,0.10 and 0.81.When pLDH/pADA≥ 19.48,above indicators are as follows:96.00%,85.00%,6.14,0.05 and 0.80.When pLDH/pADA≤10.19,the indicator are as follows:69.00%,98.00%,34.5,0.32 and 0.67.[Conclusion]In this study,the pLDH/pADA in TPE group was significantly lower than that in MPE group and PPE group.The pLDH/pADA≤15.04 as a biomarker threshold for the diagnosis of TPE has high SEN and SPE.When the pLDH/pADA≥19.48,it has great diagnostic value for excluding TPE.When pLDH/pADA≤10.19,it is helpful for the definite diagnosis of TPE.And this parameter can be obtained through routine pleural fluid biochemical analysis,which can be used as a reference index for clinicians to assist or excluse the diagnosis of TPE and differentiate TPE from MPE and PPE.