NL09-005 SOP for Performing the Direct Antiglobulin Test Ver 3

Provincial BloodCoordinating ProgramStandard Operating Procedure forPerforming the Direct AntiglobulinTest.8.2 Interpretation using Monospecific antiglobulin reagents:Anti-IgG Anti-Control Test Result InterpretationComplementNegative Negative Negative NegativePositive Positive Negative Positive – IgG and Complement coatingcellsPositive Negative Negative Positive – IgG coating cellsNegative Positive Negative Positive – Complement coating cellsNegative TNP Negative Neonate specimens only: NegativePositive TNP Negative Neonate specimens only: Positive – IgGcoating cellsPositive Positive or Positive Unable to report See Procedural Note 9.4TNP*TNP - Test not performed9.0 Procedural Notes9.1 Invalid tests9.1.1 The addition of IgG control cells should demonstrate a 2+reaction or the test is invalid and shall be repeated.9.1.2 The addition of complement control cells should demonstrate a1+ reaction or the test is invalid and shall be repeated.9.2 False Negative test9.2.1 Tests should be read immediately after centrifugation. Delaymay cause bound IgG to dissociate from the red cells causingfalse negative results.9.3 False Positive test9.3.1 False positive test results due to in vitro coating withcomplement may occur if testing is performed on a clottedspecimen.9.4 Positive Control9.4.1 A positive control may be due to strong cold agglutinin in therecipient’s serum/plasma. Wash recipient cells with 37°C andrepeat DAT.9.5 Mixed Field Reaction9.5.1 Mixed Field reaction may indicate a transfusion reaction.9.6 Weak Anti-complement Reactions9.6.1 Weak anti-complement reactions may be enhanced if tubescontaining polyspecific AHG/red cells or anti-complement/ redcells are incubated for 5 minutes at room temperature afterinitial reading of the test. Centrifuge and read again._______________________________________________________________________This document may be incorporated into each Regional Policy/Procedure Manual.NL09-005Version: 3.0Effective Date: 2012-09-30Page 10 of 12