title: Rheumatoid factor interference of α-fetoprotein evaluations in human serum by ELISA.
abstract: BACKGROUND
  Serum a-fetoprotein (AFP) is one of the most common diagnostic markers for hepatocellular cancer (HCC) in the laboratory. As other immunoassays, AFP determination is not free from interferences. Natural antibodies like rheumatoid factors (RFs) may induce falsely elevated results, leading to misdiagnosis and expensive unnecessary explorations.
  
  
  METHODS
  Serum samples containing AFP were spiked with moderate- or high-concentration RFs, and samples with high RF levels were spiked with AFP. The original sera, as well as the mixtures were tested for AFP by one-step and two-step sandwich ELISA.
  
  
  RESULTS
  In the spiked specimens, addition of RFs caused significant bias in the measurement of AFP. The threshold for triggering significant interference was 260 IU/mL for RFs and 74 ng/mL for AFP.
  
  
  CONCLUSIONS
  In studies on the prevalence and clinical significance of serum AFP, RF interference should be considered and RF testing should be performed.
authors: Xiaoxia
authors: X
authors: Zhu
authors: Yuyingguo
authors: Zhenyun
authors: Z
authors: Huang
authors: Shumei
authors: S
authors: Yang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000097:blood / Q000175:diagnosis*; D004797:Enzyme-Linked Immunosorbent Assay / Q000592:standards; D005189:False Positive Reactions; D006801:Humans; D008113:Liver Neoplasms / Q000097:blood / Q000175:diagnosis*; D008875:Middle Aged; D011237:Predictive Value of Tests; D011933:Reagent Kits, Diagnostic; D012015:Reference Standards; D015203:Reproducibility of Results; D012217:Rheumatoid Factor / Q000097:blood*; D055815:Young Adult; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: C097353:AFP protein, human; D011933:Reagent Kits, Diagnostic; D000509:alpha-Fetoproteins; D012217:Rheumatoid Factor