Sitter Thomas, Schmidt Martin, Schneider Susanne, Schiffl Helmut
Department of Nephrology, Medizinische Klinik-Innenstadt, Ludwig-Maximilians-University, Munich, Germany.
J Nephrol. 2002 May-Jun;15(3):297-301.
Early diagnosis of bacterial infection in renal patients remains difficult. Common laboratory parameters, such as white blood cell (WBC) count, erythrocyte sedimentation rate, and C-reactive protein (CRP) may be affected by the underlying disease, uremia or its extracorporeal treatment, or by immunosuppressive drugs. Procalcitonin (PCT) may be useful for the detection of systemic bacterial infections in patients with end-stage renal disease (ESRD) undergoing renal replacement therapy, but elevated PCT concentrations have also been found in a significant number of uremic patients without signs of infection.
We tested whether measurements of PCT levels help distinguish the chronic inflammation in renal diseases from invasive bacterial infections. Serum levels of PCT were compared with the corresponding serum C-reactive protein (CRP) concentrations and WBC counts in 197 patients with different stages of renal disease: Group I) 32 patients with chronic renal failure (serum creatinine 2-6 mg/dL); group II) 31 patients with a functioning renal transplant receiving standard immunosuppressive regimens; group III) 76 clinically stable patients with ESRD undergoing hemodialysis (HD); group IV) 23 patients with chronic renal failure (CRF) due to systemic autoimmune disease; group V) 35 patients with proven systemic bacterial infection and CRF.
PCT levels were within the normal range (< 0.5 ng/mL) in patients with CRF and renal transplant patients without any clinical evidence of bacterial infection, regardless of the degree of renal failure and the underlying disorders. In 22 out of 76 stable HD patients, PCT levels were above the upper limit of normal, but 97% of these values were below the proposed cut-off for chronic HD patients of < 1.5 ng/mL. CRP levels were elevated in 17 of 32 patients with CRF (mean +/- SD: 0.57 +/- 0.49 mg/dL), in 10 of 31 renal transplant patients (0.41 +/- 0.55 mg/dL), in 16 of 23 patients with autoimmune disorders (2.78 +/- 3.21 mg/dL) and in 42 of 76 patients treated by HD (0.64 +/- 0.58 mg/dL). In patients with CRF and systemic bacterial infections, both PCT and CRP were markedly elevated (PCT 61.50 +/- 115.4 ng/mL, CRP 14.50 +/- 10.36 mg/dL), but in contrast to PCT, CRP values overlapped in infected and non-infected patients.
Our data indicate that PCT levels are not significantly affected by loss of renal function, immunosuppressive agents or autoimmune disorders. Thus, significantly elevated PCT concentrations offer good sensitivity and specificity for the early diagnosis of systemic bacterial infection in patients with CRF or patients with ESRD treated by HD. CRP concentrations may be useful indicators for inflammation in patients with renal diseases, but have low specificity for the diagnosis of bacterial infection.
肾病患者细菌感染的早期诊断仍然困难。常见的实验室指标，如白细胞（WBC）计数、红细胞沉降率和C反应蛋白（CRP）可能会受到基础疾病、尿毒症或其体外治疗的影响，或受到免疫抑制药物的影响。降钙素原（PCT）可能有助于检测接受肾脏替代治疗的终末期肾病（ESRD）患者的全身性细菌感染，但在大量无感染迹象的尿毒症患者中也发现PCT浓度升高。
我们测试了PCT水平的测量是否有助于区分肾病中的慢性炎症与侵袭性细菌感染。比较了197例不同阶段肾病患者的血清PCT水平与相应的血清C反应蛋白（CRP）浓度和WBC计数：第一组）32例慢性肾衰竭患者（血清肌酐2 - 6mg/dL）；第二组）31例接受标准免疫抑制方案的肾移植功能正常患者；第三组）76例临床稳定的接受血液透析（HD）的ESRD患者；第四组）23例因全身性自身免疫性疾病导致慢性肾衰竭（CRF）的患者；第五组）35例经证实有全身性细菌感染和CRF的患者。
CRF患者和无任何细菌感染临床证据的肾移植患者的PCT水平在正常范围内（<0.5ng/mL），无论肾衰竭程度和基础疾病如何。76例稳定的HD患者中有22例PCT水平高于正常上限，但这些值的97%低于慢性HD患者建议的<1.5ng/mL的临界值。32例CRF患者中有17例CRP水平升高（平均±标准差：0.57±0.49mg/dL），31例肾移植患者中有10例（0.41±0.55mg/dL），23例自身免疫性疾病患者中有16例（2.78±3.21mg/dL），76例接受HD治疗的患者中有42例（0.64±0.58mg/dL）。在CRF和全身性细菌感染患者中，PCT和CRP均显著升高（PCT 61.50±115.4ng/mL，CRP 14.50±10.36mg/dL），但与PCT不同的是，CRP值在感染和未感染患者中重叠。
我们的数据表明，PCT水平不受肾功能丧失、免疫抑制剂或自身免疫性疾病的显著影响。因此，PCT浓度显著升高对CRF患者或接受HD治疗的ESRD患者全身性细菌感染的早期诊断具有良好的敏感性和特异性。CRP浓度可能是肾病患者炎症的有用指标，但对细菌感染的诊断特异性较低。
