Variation in Pipetting May Lead to the Decreased Detection of Antibodies in Manual Gel Testing

Sharon Bobryk; Linda Goossen

doi:10.29074/ascls.24.3.161

This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.

Sharon Bobryk, MSA, MLS(ASCP)SBB^CM⇑
1. Beaumont Laboratory, Royal Oak, MI
Linda Goossen, PhD, MT (ASCP)
1. College of Health Professions, Grand Valley State University, Grand Rapids, MI

Address for Correspondence: Sharon Bobryk, MSA, MLS(ASCP)SBB^CM, Medical Laboratory Scientist, Clinical Pathology, Blood Bank, Beaumont Laboratory, 3601 W. 13 Mile Road, Royal Oak, MI 49313, (248) 898-9010, sharon.bobryk{at}beamont.edu

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.

STUDY DESIGN AND 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).

CONCLUSION: 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.