Uncertainty in measurement for 43 biochemistry, immunoassay, and hemostasis routine analytes evaluated by a method using only external quality assessment data
Résumé
Background: International organizations require from medical laboratories a quantitative statement of the uncertainty in measurement (UM) to help interpret patient results. The French accreditation body (COFRAC) recommends an approach (SH GTA 14 IQC/EQA method) using both internal quality control (IQC) and external quality assessment (EQA) data. The aim of this work was to validate an alternative way to quantify UM using only EQA results without any need for IQC data. This simple and practical method, which has already been described as the long-term evaluation of the UM (LTUM), is based on linear regression between data obtained by participants in EQA schemes and target values. We used it for 43 routine analytes covering biochemistry, immunoassay, and hemostasis fields. Methods: Data from 50 laboratories participating in ProBioQual (PBQ) EQA schemes over 25 months were used to obtain estimates of the median and 90th percentile LTUM and to compare them to the usual analytical goals. Then, the two UM estimation methods were compared using data from 20 laboratories participating in both IQC and EQA schemes. Results: Median LTUMs ranged from 2.9% (sodium) to 16.3% (bicarbonates) for biochemistry analytes, from 12.6% (prothrombin time) to 18.4% (factor V) for hemostasis analytes when using the mean of all participants, and were around 10% for immunoassays when using the peer-group mean. Median LTUMs were, in most cases, slightly lower than those obtained with the SH GTA 14 method, whatever the concentration level. Conclusions: LTUM is a simple and convenient method that gives UM estimates that are reliable and comparable to those of recommended methods. Therefore, proficiency testing (PT) organizers are allowed to provide participants with an additional UM estimate using only EQA data and which could be updated at the end of each survey.
Mots clés
biochemistry
blood clotting time
gamma glutamyl transferase blood level
human
iron blood level
lactate dehydrogenase blood level
linear regression analysis
major clinical study
partial thromboplastin time
phosphate blood level
potassium blood level
priority journal
prothrombin time
sodium blood level
triacylglycerol blood level
triacylglycerol lipase blood level
urea blood level
evaluation study
health care quality
procedures
statistical model
Hemostasis
Humans
Immunoassay
Linear Models
Quality Assurance
Health Care
Quality Control
Uncertainty
alanine aminotransferase
alkaline phosphatase
alpha fetoprotein
amylase
aspartate aminotransferase
bicarbonate
bilirubin
CA 125 antigen
CA 15-3 antigen
CA 19-9 antigen
calcium
carcinoembryonic antigen
chloride
cholesterol
creatine kinase
creatinine
creatine kinase blood level
chloride blood level
calcium blood level
follitropin blood level
external quality assessment
follitropin
gamma glutamyltransferase
glucose
iron
lactate dehydrogenase
magnesium
phosphate
potassium
prostate specific antigen
sodium
triacylglycerol
triacylglycerol lipase
urate
urea
alanine aminotransferase blood level
alkaline phosphatase blood level
alpha fetoprotein blood level
Article
aspartate aminotransferase blood level
bicarbonate blood level
bilirubin blood level