title: The effect of paraproteins on the erythrocyte sedimentation rate: a comparison between the StarrSed and TEST 1.
abstract: BACKGROUND
  The principle of the erythrocyte sedimentation rate (ESR) as assessed by TEST 1 is different from that of Westergren-based methods. This could result in different influences on the tests by paraproteins.
  
  
  METHODS
  We investigated the effect of paraproteins on ESR readings by TEST 1 (y) and the StarrSed (x), a Westergren-based method, in 142 patients with paraproteinaemia. Agreement (Passing-Bablok) and bias (Bland-Altman) between methods was investigated and compared with that of a control population.
  
  
  RESULTS
  A poor agreement between the two methods was found in patients with a paraprotein (y = 0.67x + 3.3) in comparison with that of the control population (y = 0.96x + 0.2). Large differences between methods were present when ESR readings were >40 mm/hour, but clinical interpretation was similar in 90% of cases. Linear regression showed a concentration dependent influence of paraproteins on ESR readings by the StarrSed, especially for immunoglobulin class IgM.
  
  
  CONCLUSIONS
  ESR readings by TEST 1 result in similar clinical interpretation for most subjects, but readings are less influenced by the presence of a paraprotein than those of a Westergren-based method.
authors.affiliation: Laboratory of Clinical Chemistry, Máxima Medical Centre, Veldhoven, The Netherlands. m.raijmakers@mmc.nl
authors.forename: Maarten T M
authors.initials: MT
authors.lastname: Raijmakers
authors.forename: Philip H M
authors.initials: PH
authors.lastname: Kuijper
authors.forename: Dirk L
authors.initials: DL
authors.lastname: Bakkeren
authors.forename: Huib L
authors.initials: HL
authors.lastname: Vader
mesh_terms: D001799:Blood Sedimentation; D016022:Case-Control Studies; D006403:Hematologic Tests / Q000379:methods / Q000706:statistics & numerical data; D006801:Humans; D010265:Paraproteinemias / Q000097:blood; D010266:Paraproteins / Q000378:metabolism*
chemical_list: D010266:Paraproteins