Bush T M, Shlotzhauer T L, Grove W
Department of Medicine, Santa Clara Valley Medical Center, San Jose, Calif.
Arch Intern Med. 1993 Oct 25;153(20):2363-6. doi: 10.1001/archinte.153.20.2363.
The diagnostic value of serum complement testing is well established in inherited complement deficiencies and glomerulonephritis. Their utility is less certain in diagnosing rheumatic diseases. We noted that complement tests were frequently ordered for patients who were referred to our rheumatology clinic. We sought to determine the clinical rationale for ordering complement tests in our hospital and the effect of the test results in patients with rheumatic diseases.
We conducted a retrospective medical chart review of patients who had serum complement tests ordered at our hospital. We determined whether the test was ordered as a diagnostic tool in a patient with a suspected rheumatic disease. In these cases, we attempted to correlate the results of the complement tests with the patient's eventual diagnosis.
We obtained the medical charts of 130 patients who had 307 complement assays (C3, C4, or total hemolytic complement) performed between October 1988 and July 1989. The tests were ordered for diagnostic reasons in 68% of the patients; 54% of these were ordered by nonspecialists. The complement tests were ordered on 28 patients with suspected rheumatic diseases. The three patients with hypocomplementemia did not have a connective tissue disease. The 10 patients who eventually were diagnosed as having rheumatic disease all had normal serum complement levels. Additionally, we found that 77% of patients had more than one complement assay ordered. The test results were discordant in only 24% of these cases.
Complement screening is not a useful diagnostic test in most patients with suspected rheumatic disease. Despite their lack of established diagnostic value, these tests were frequently performed in our hospital. Judicious use of complement testing would provide substantial cost savings without a loss of clinically relevant information. When the complement testing is clinically indicated, clinicians should consider using a single C3 assay initially rather than multiple assays unless a hereditary deficiency is suspected.
血清补体检测在遗传性补体缺陷和肾小球肾炎中的诊断价值已得到充分确立。其在诊断风湿性疾病中的作用尚不确定。我们注意到，经常有患者被转介到我们的风湿病诊所进行补体检测。我们试图确定在我院进行补体检测的临床依据以及检测结果对风湿性疾病患者的影响。
我们对在我院进行血清补体检测的患者进行了回顾性病历审查。我们确定该检测是否作为疑似风湿性疾病患者的诊断工具而进行。在这些病例中，我们试图将补体检测结果与患者最终的诊断相关联。
我们获取了1988年10月至1989年7月期间进行了307次补体检测（C3、C4或总溶血补体）的130例患者的病历。68%的患者进行检测是出于诊断原因；其中54%是由非专科医生开具的检测单。对28例疑似风湿性疾病的患者进行了补体检测。3例补体水平降低的患者没有结缔组织病。最终被诊断为患有风湿性疾病的10例患者血清补体水平均正常。此外，我们发现77%的患者进行了不止一项补体检测。这些病例中检测结果不一致的仅占24%。
补体筛查对大多数疑似风湿性疾病的患者并非有用的诊断检测。尽管这些检测缺乏既定的诊断价值，但在我院仍经常进行。明智地使用补体检测将在不损失临床相关信息的情况下大幅节省成本。当临床上有补体检测指征时，除非怀疑有遗传性缺陷，临床医生应首先考虑使用单一的C3检测而非多项检测。
