title: Variation in pipetting may lead to the decreased detection of antibodies in manual gel testing.
abstract: BACKGROUND
  Variation in pipetting technique can contribute to the failed detection of weakly reactive antibodies. This study evaluated the impact of pipetting technique on the sensitivity of antibody detection using the manual gel test.
  
  
  METHODS
  A total of 115 plasma antibodies were evaluated using the manual gel test (Ortho ID-MTS, Raritan, NJ). All antibodies were diluted to obtain 1+, w+, and undetectable reactions. Testing was performed in parallel using two pipetting techniques: cells and plasma pipetted into the gel card to allow an air gap and without an air gap.
  
  
  RESULTS
  When cells and plasma were pipetted into the gel card without air gap, 12.4% of 1+ reactions (p < 0.001) and 81.0% of w+ reactions (p < 0.001) were not detected. Overall, 24.7% of clinically significant (p < 0.001) and 29.7% of nonspecific antibodies (p < 0.05) became nonreactive. Antibody screening tests failed to detect 26.0% of passively acquired anti-D (p < 0.001), 38.0% of anti-E (p < 0.001), 28.0% of anti-Jk(a) (p < 0.001), 20.0% of anti-K (p < 0.05), and 35.0% of warm auto antibodies (p < 0.05).
  
  
  CONCLUSIONS
  Cells and plasma pipetted manually without leaving an air gap in the gel card failed to detect clinically significant antibodies. An optimal pipetting technique is recommended to ensure the detection of weakly reactive antibodies.
authors: Clinical Pathology, Blood Bank, Beaumont Laboratory, 3601 W 13 Mile Road, Royal Oak, MI 49313, USA. sharon.bobryk@beamont.edu
authors: Sharon
authors: S
authors: Bobryk
authors: Linda
authors: L
authors: Goossen
mesh_terms: D000906:Antibodies / Q000097:blood*; D002850:Chromatography, Gel; D019411:Clinical Laboratory Techniques / Q000295:instrumentation / Q000379:methods; D006801:Humans; D012680:Sensitivity and Specificity
chemical_list: D000906:Antibodies