Report of a trial with lyophilised QC sera in the CMCH/ACBI EQAS programmes in India
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Published on: April 18, 2016
R Selvakumar1, S Swaminathan, J J Fleming
1Department of Clinical Biochemistry, Christian Medical College and Hospital, Vellore, Tamil Nadu.
Insights
Lyophilized quality control (QC) materials are suitable for laboratory use, showing no performance deterioration compared to liquid QC. This study confirms good stability and reconstitution techniques for lyophilized QC in clinical chemistry.
Area of Science:
- Clinical Chemistry
- Laboratory Medicine
- Quality Control
Background:
- Lyophilized quality control (QC) materials were introduced to supplement existing liquid QC programs.
- The study involved 240 laboratories over six months, assessing 18 analytes, including new additions like LDH and triglycerides.
- Ion-selective electrode (ISE) methods were used for sodium and potassium measurements in QC for the first time.
Purpose of the Study:
- To compare laboratory performance using lyophilized QC versus liquid QC.
- To evaluate the stability and effectiveness of lyophilized QC materials.
- To identify potential standardization issues with specific analytes and methods.
Main Methods:
- Statistical comparison of methodwise mean variance index score (MVIS) values.
- Analysis of performance for 18 analytes using lyophilized QC materials.
- Evaluation of laboratory ranking patterns based on overall MVIS (OMVIS).
Main Results:
- Laboratory performance was similar for five analytes (glucose, albumin, cholesterol, SGOT, SGPT) between liquid and lyophilized QC.
- Performance was significantly better for urea, calcium, and creatinine with lyophilized QC.
- Significant differences were noted for total protein, sodium, potassium, and ALP, with a negative bias for sodium and potassium ISE methods.
Conclusions:
- Introduction of lyophilized QC does not degrade laboratory performance.
- Lyophilized QC materials exhibit good stability and support effective reconstitution techniques.
- The study identified specific areas for improvement, including standardization of LDH and amylase reporting and sodium/potassium ISE methods.
Abstract:
2000 vials of lyophilized QC of two different levels (low and high) were donated by Roche Diagnostics GmbH, through the IFCC and received by CMCH in June 2001. A total of 240 la boratories were enrolled for this 6 month pilot study. In addition to the 12 analytes in the liquid QC programme, six additional analytes, LDH, triglyceride, urate, total bilirubin, phosphate and amylase were included. It was also possible to measure sodium and potassium by ion selective electrode (ISE) methods in the QC for the first time.The performance of the laboratories for the existing 12 analytes using liquid stabilized QC was compared to the performance using lyophilized QC. Using a statistical comparison of the methodwise mean variance index score (MVIS) values, five assays viz glucose, albumin, cholesterol, and SGOT and SGPT performance was the same in liquid QC and lyophilized QC. Three assays viz urea, calcium and creatinine were significantly better, and 4 assays total protein, sodium, potassium and ALP were significantly worse. However the overall VIS (OMVIS) for the laboratories was the same and the ranking pattern of this 6 month OMVIS was also unaltered.The lyophilized QC scheme highlighted a negative bias between flame and ISE methods for sodium and potassium, and a definite standardization problem in reporting LDH and amylase results, but triglyceride, urate and total bilirubin assays were performing well.It was concluded that the introduction of lyophilized QCs will not cause any deterioration of performance to participating laboratories. Stability of the material seems to be good and the laboratories are generally using a good reconstitution technique.
