J Clin Pathol Qual Control.  1998 Jun;20(1):163-167.

Experience of Total Error Reduction by the Improvement of Control Sera Storage Condition for Clinical Chemistry Tests using Autoanalyzer

• Chang SW
• Hwang BC
• Kim W
• Lee NH

Abstract

BACKGROUND: Determination of total error (TE) is a kind of practice for the evaluation of laboratory test performance. TE can be calculated as the sum of random and systematic error (SE). It may be erroneously calculated due to inappropriate storage of control material. We compared TE between two storage conditions of control material.
METHODS
We calculated TE of 18 chemistry items using two levels of commercial control sera with Hitachi 7150 chemistry autoanalyzer for 16 months. We compared TE of two storage conditions of control sera, one of which had been storage at room temperature up to 7 hours for first 8 months and the other which had been stored as a few frozen aliquots after first determination and determined within 1 hour after thawing in the same dat for the remaining 8 months.
RESULTS
We found CK have largest SE, followed by ALP, glucose and gamma-GT. CK also showed the largest RE, followed by LD. CK also showed the largest TE, followed by LD. By improving the storage condition, we observed decrease of TE of CK, ALP, and LD.
CONCLUSIONS
By improving the storage condition of chemistry control sera, namely, aliquoting, storing them in freezer and using within one hour after thawing them, instead of storing them in room temperature during daily operation of autochemistry analyzer, reduced the false increase of total errors, especially CK, ALP, and LD.

MeSH Terms

Chemistry
Chemistry, Clinical*
Clinical Chemistry Tests*
Glucose
Total Quality Management
Glucose