Rheumatoid factor measurement--continuing problems 70 years after discovery

Clinical Rheumatology, 04/11/2011

Ameratunga R et al. – Standardization for rheumatoid factor (RF) measurement is not optimal and has not been achieved between these two commonly used instruments. This may have clinical implications for patient management.


  • Compared RF results between 2 commonly used commercial instruments
  • Serum samples exchanged between laboratory using Beckman Immage immunonephelometer and another using Roche Modular immunoturbidimeter
  • The World Health Organization (WHO) reference standard for RF (W1066) used to compare 2 methods


  • The Roche immunoturbidimeter appears to have superior sensitivity
  • Significant bias between 2 instruments as levels of RF increase
  • Results from WHO RF reference preparation correlated most closely with results from Roche immunoturbidimeter

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