ASSESSMENT OF PERFORMANCE OF ROUTINECLINICAL
BIOCHEMISTRY TESTS BASED ON TOTAL ALLOWABLE ERROR
CRITERIA IN A TERTIARY CARE HOSPITAL
Zeenath Latheef , Jyothi D N
Department of Biochemistry ,St. John’s Medical College and Hospital, Bengaluru
Introduction
Total allowable error (TEa) is the analytical quality specification that determines the
acceptable limits for a test result. Physicians request laboratory tests for
approximately 80% of patients presenting to the hospital. Considering this, it is very
important to prevent errors by improving the quality of each testing procedure. Total
Allowable Error can be used to benchmark test performance. The laboratory results
are important to diagnose and manage the disease. To produce reliable results,
laboratories are aimed to adopt the best quality assurance program. Besides maintain
a good compliance for required standards, errors are not uncommon within the
laboratory process system.
Aims and Objectives
Aim: To assess the performance of routine clinical biochemistry tests based on total
allowable error criteria in a tertiary care hospital
Total occurrence of TEobs >TEa from Jan21-Dec 21
12
• A retrospective study performed at Clinical Biochemistry Laboratory of St. John’s
Medical College Hospital, Bengaluru, India.
• A Total of 88 analytes internal quality control data of all the levels that are
accepted for analytical runs was obtained from Unity Real Time (URT) software,
Bio-Rad Laboratories, Inc. and was analysed retrospectively over a period of 1
year from January 2021- December 2021.
• Using these data, for each Quality Control Material (QCM) and each analyte Mean, SD and CV, Peer mean and bias was obtained. Observed total error
(TEobs) was calculated using measured CV and measured bias, according to the
formula:
TE (obs) = 1.65×CV + Bias%.
• An independent t test was performed to compare the analytes which were done
common in both instruments(Abbott Architect ci8200 Ⅰ and Abbott Architect
ci8200 Ⅱ)
If TEobs is higher than TEa, then the quality requirement is not met, and thus
corrective actions is suggested.
STATISTICAL ANALYSIS: done using SPSS.20
Descriptive statistical analysis
Independent sample t test
 Significance is assessed at 5 % level of significance.
Results
Independent sample t test
In about 20 analytes which were commonly done in both instruments, difference in
TEobs was significant in parameters such as Glucose, creatinine(level-2), LDL, Total
protein(level-2), albumin(level-1), AST, ALT, GGT, Sodium, Potassium and TSH.
There were no significant differences in Total error observed in other analytes
8
6
4
2
0
Creatinine
Cholesterol, HDL
LDH
Ethanol
T3, Total
T4, Total
Ferritin
T3, Free
T4, Free
Homocysteine
Cholesterol, HDL(A2)
ALT
LH
Prolactin
PTH
Phenobarbital
Phenytoin
Carbamazepine
Ceruloplasmin
Metanephrines
Serum Lithium
HbA1c
pco2
po2
ionized Calcium
Osmolality-urine
Serum Osmolality
Methods
10
No of Months
Objectives:
1.To determine the observed Total error of routine clinical biochemistry analytes in
the laboratory
2.To compare the observed total error with the total allowable error for analytes as
established by standard guidelines.
3.To validate quality of analytical phase by evaluating the total allowable error of
biochemistry analytes for our laboratory method and instruments at a hospital
laboratory.
Conclusion
From the study it is evident that TEobs was acceptable for most of the analytes
in our laboratory. Also, the analytical performance was acceptable.
This study can be an aid in deciding benchmark for the acceptable level of
TEobs for our laboratory, also it provides the objective idea of source of error;
thus, TEobs could be included as one of the Quality indicators in clinical
chemistry laboratory.
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