The Investigation Of The Value Of PCT In The Diagnosis And Guiding De-escalation Therapy Of Severe Infection In Children

Objective：With the measurement of the levels of the serum procalcitonin(PCT), highsensitivity C-reactive protein(hs-CRP) and peripheral blood white blood cellcount(WBC) among the children with serious bacterial infection,local bacterialinfection and non-bacterial infection and the comparison between the change of theserious bacterial infectious children`s serum procalcitonin(PCT) levels before and aftertreatment, this paper aims to investigate the application value of PCT in the diagnosisand guiding de-escalation therapy for severe infectious children.Methods: From January2012to February2013,243children patients were divided intonon-bacterial infection group(112cases), serious bacterial infection group (68cases)andlocal bacterial infection group (63cases).All patients were tested bloodroutine,biochemistry,hs-CRP,PCT,blood culture and related auxiliary examinationwithin24hours after admission. Those patients were treated with antibiotics that wereselected according to related laboratory examination and diagnosis.The serious bacterialinfection group were treated with antibiotics according to de-escalation therapy, and onthe third day, when their clinical manifestation was improved, they were tested bloodroutine,hs-CRP, PCT and others again.Then according to PCT-lowering level,theserious bacterial infection group made de-escalation therapy.The Skewness measurement data was expressed as the median and quartile range withbeing analyzed by using KRUSKAL-Wallis H test. Receiver operator characteristiccurve(ROC) was drawn and areas under these curves were calculated on bacterial infection group. According to every golden standard(PCT>0.5ng/ml,hs-CRP>3mg/L,WBC>10*109/L),the sensitivity and specificity were calculated. SPSS13.0softwarewere used for statistical analysis. Difference was considered significantly by P valueless than0.05.Results:1、The serum PCT,hs-CRP and WBC in serious bacterial infection group wereincreased significantly. The serum PCT and WBC in local bacterial infection groupwere slightly increased while hs-CRP was significantly increased. The serumPCT,hs-CRP and WBC in non-bacterial infection group were insignificantly increased.2、The difference of PCT,hs-CRP and WBC level between the serious bacterial infectiongroup and local bacterial infection group was significant(P<0.05).The difference of PCT and hs-CRP between the serious bacterial infection group andnon-bacterial infection group was significant (P<0.05).The difference of PCT andhs-CRP level between the local bacterial infection group and non-bacterial infectiongroup was significant (P<0.05), but there was no significant difference in WBC countbetween the two groups (P>0.05).3、The AUC of PCT and hs-CRP were0.90and0.654on bacterial infection group and the difference were significant（P<0.05）.The AUC ofPCT and WBC were0.90and0.623on bacterial infection group and the difference weresignifican（tP<0.05）. The sensitivity of PCT,hs-CRP and WBC were92.6%、83.8%and54.4%individually but specificity were66%、30.2%and63.5%individually.Thesensitivity and specificity of PCT were higher than hs-CRP and WBC.4、Throughdynamic observation of serious bacterial infection group, the levels of PCT and hs-CRPbefore treatment were significantly different from those after treatment(P<0.05).5、Thedifference of hospitalization days and treatment cost between guided by PCT and noguided by PCT guiding de-escalation therapy groups was significant(P<0.05).Conclusion：1、The level of PCT in the diagnosis of systemic bacterial infection has preferable sensitivity and specificity, and it can be used as a reliable indicator todiagnose bacterial infection.2、PCT can reflect the severity of bacterial infection, thehigher its levels, the more severe condition.3、Through dynamic observation, the levelof PCT can reflect the change of illness and assess the condition of it.4、The serum PCTcan reflect the efficacy of antibiotics, and it can be used as a basis to adjust antibiotics inde-escalation therapy for clinician.