Abstract
Point-of-care (POC) testing within hemostasis is an expanding field, with the most
widely used test being POC international normalized ratio (INR). Many of these devices
are being used in a nonlaboratory setting by staff with no laboratory training. In
the United Kingdom, external quality assessment (EQA) is provided by the organization
UK National External Quality Assessment Scheme for Blood Coagulation (UK NEQAS BC).
Participants within the UK NEQAS BC POC INR program are largely based in primary care
(77%), with the majority of EQA samples and patients tests being performed by nurses
(70%). Many of these centers do not have support from the laboratory staff and may,
therefore, not understand the requirement for a robust quality control (QC) system
comprising both internal quality control (IQC) and EQA. From data acquired through
a questionnaire of these UK NEQAS BC users, we observed that 2% of the centers never
perform IQC tests, only 29% perform IQC tests when starting a new batch of test strips,
and just 15% carry out IQC with each clinic as recommended by the UK guidelines. The
imprecision of EQA tests was greater for POC users than in the UK NEQAS BC hospital
laboratory program, with average coefficients of variation for a 2-year period of
11.0 and 7.3%, respectively. This may reflect the handling of EQA samples rather than
the imprecision of the method, due to the lack of laboratory training amongst POC
staff. POC INR in the UK could greatly benefit from more interaction and support from
laboratories to these POC testers.
Keywords
point of care - INR monitoring - primary care - secondary care
