Department of Infectious Diseases, Örebro University Hospital, S-701 85 Örebro, Sweden.
BMC Infect Dis. 2014 Mar 21;14:155. doi: 10.1186/1471-2334-14-155.
The commercial test, SeptiFast, is designed to detect DNA from bacterial and fungal pathogens in whole blood. The method has been found to be specific with a high rule-in value for the early detection of septic patients. The software automatically provides information about the identified pathogen, without quantification of the pathogen. However, it is possible to manually derive Crossing point (Cp) values, i.e. the PCR cycle at which DNA is significantly amplified. The aim of this study was to find out whether Cp values correlate to disease severity.
We used a study cohort of patients with positive results from SeptiFast tests for bacteria from a recent study which included patients with suspected sepsis in the Emergency department. Cp values were compared with disease severity, classified as severe sepsis/septic shock or non-severe sepsis, according to the criteria of the American College of Chest Physicians/Society of Critical Care Medicine.
Ninety-four patients were included. The prevalence of severe sepsis/septic shock in the study was 29%. SeptiFast positive tests from patients with severe sepsis/septic shock had significantly lower Cp values compared with those from patients with non-severe sepsis, median 16.9 (range: 7.3-24.3) versus 20.9 (range: 8.5-25.0), p < 0.001. Positive predictive values from the SeptiFast test for identifying severe sepsis/septic shock were 34% at Cp cut-off <25.0, 35% at Cp cut-off <22.5, 50% at Cp cut-off <20.0, and 73% at Cp cut-off <17.5. Patients with a positive Septifast test with a Cp value <17.5 had significantly more severe sepsis/septic shock (73% versus 15%, p < 0.001), were more often admitted to the Intensive Care Unit (23% versus 4%, p = 0.016), had positive blood culture (BC) more frequently (100% versus 32%, p < 0.001) and had longer hospital stays (median 19.5 [range: 4-78] days versus 5 [range: 0-75] days, p < 0.001) compared with those with a Cp value >17.5.
Our results suggest that introducing quantitative data to the SeptiFast test could be of value in assessing sepsis severity. Moreover, such data might also be useful in predicting a positive BC result.
商业检测 SeptiFast 旨在检测全血中的细菌和真菌病原体的 DNA。该方法已被证明具有特异性，对早期检测脓毒症患者的规则值较高。该软件可自动提供有关鉴定病原体的信息，而无需对病原体进行定量。但是，可以手动推导循环阈值 (Cp) 值，即 DNA 显著扩增的 PCR 循环。本研究的目的是确定 Cp 值是否与疾病严重程度相关。
我们使用了最近一项研究中 SeptiFast 检测细菌阳性结果的患者研究队列，该研究包括急诊科疑似脓毒症患者。Cp 值与疾病严重程度进行了比较，根据美国胸科医师学院/危重病医学会的标准，将其分类为严重脓毒症/脓毒性休克或非严重脓毒症。
共纳入 94 例患者。研究中严重脓毒症/脓毒性休克的患病率为 29%。与非严重脓毒症患者相比，严重脓毒症/脓毒性休克患者的 SeptiFast 阳性测试的 Cp 值明显较低，中位数为 16.9（范围：7.3-24.3）与 20.9（范围：8.5-25.0），p<0.001。SeptiFast 测试对严重脓毒症/脓毒性休克的阳性预测值在 Cp 截止值<25.0 时为 34%，在 Cp 截止值<22.5 时为 35%，在 Cp 截止值<20.0 时为 50%，在 Cp 截止值<17.5 时为 73%。Cp 值<17.5 的 Septifast 阳性测试患者的严重脓毒症/脓毒性休克发生率明显更高（73%比 15%，p<0.001），入住重症监护病房（23%比 4%，p=0.016）的频率更高，血培养阳性（BC）的频率更高（100%比 32%，p<0.001），住院时间更长（中位数 19.5[范围：4-78]天比 5[范围：0-75]天，p<0.001）与 Cp 值>17.5 的患者相比。
我们的结果表明，将定量数据引入 SeptiFast 测试可能有助于评估脓毒症的严重程度。此外，此类数据也可能有助于预测阳性 BC 结果。
