"Carryback": effect of viscous liquid controls on the preceding sample analyzed with the SMA II continuous-flow analyzer
We systematically studied the "carryback" effect of ethylene glycol-based controls on the preceding sample on an SMA II continuous-flow analyzer. Including Beckman Level 1 unassayed liquid control material as a sample lowered the 12 analyte values of the preceding sample by an average of 2...
Saved in:
Published in | Clinical chemistry (Baltimore, Md.) Vol. 31; no. 11; pp. 1896 - 1899 |
---|---|
Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Washington, DC
Am Assoc Clin Chem
01.11.1985
American Association for Clinical Chemistry |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | We systematically studied the "carryback" effect of ethylene glycol-based controls on the preceding sample on an SMA II continuous-flow analyzer. Including Beckman Level 1 unassayed liquid control material as a sample lowered the 12 analyte values of the preceding sample by an average of 2.7%, Level 2 (the most viscous) by an average of 4.4%, and Level 3 by 3.2%. Water-reconstituted lyophilized control material caused no carryback effect, but lyophilized control reconstituted with 330 mL/L ethylene glycol decreased the preceding sample's results by 4.1% (average carryback). We believe that carryback is caused by the drag placed on the sample line by a viscous sample, which decreases the volume of the preceding sample that is delivered to the reagent or pre-dilution mixing coils. Our findings were confirmed on another SMA II. Limited study of a SMAC analyzer gave inconclusive results, but further evaluation of continuous-flow systems for carryback is warranted. Carryback substantially increases total analytical variability. |
---|---|
Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0009-9147 1530-8561 |
DOI: | 10.1093/clinchem/31.11.1896 |