PROPRIETARY INFORMATIONCONFIDENTIAL MATERIALNot for Customer Distribution Assays/ReagentsAEROSET® System Troubleshooting Guide 14194816-107—November 2004Frequently Asked Questions (FAQ)Question ResponseMULTIGENT ® Hemoglobin A 1c results do notmatch another method. Why?MULTIGENT Hemoglobin A1c is an indirectmethod, in which lower HbA 1cconcentrations produce higher signal levels.This may provide less imprecision at theselower concentrations. The readingwavelength of 604 nm minimizes interferencefrom HAMA (human anti-mouse antibodies),hemolysis, bilirubin, and lipemia.Which controls are recommended? Whichcontrols have AEROSET assay values?MULTIGENT Hemoglobin A1c controls,LN 2K96-10, are recommended for theHemoglobin A1c assay. Refer to theMULTIGENT Hemoglobin A1c Control valuesheet for control ranges.Why am I getting negative calibration rates?Is this normal?This is normal. The indirect assay methodprovides a curve in which the signal isinversely proportional to concentration, i.e.,low sample values produce the highest rates.The zero calibrator rate (highest rate) is usedas a blank and is subtracted from the rates ofall the other calibrators, causing them to benegative.How does this assay perform with specifichemoglobin variants, e.g., HbA 2, HbF, HbS?Refer to the Interfering Substances section ofthe Hemoglobin A1c package insert.The Reaction Mode for Total Hemoglobin islisted as END UP in the package insert. Whydoes the Reaction Graph appear to show anEND DOWN reaction?• This occurs because sample and reagent areadded and mixed at Read Time 1. However,it takes time for the reaction mixture tosettle. Bubbles and swirling of the mixturein the cuvette cause absorbance of thesample to start at a higher number thanwhen the final read is taken.• The reaction is classified as END UP becauseabsorbance increases with increasinganalyte concentration within the main readwindow.
