Advice
Clinical and technical evidence
Clinical and technical evidence
A literature search was carried out for this briefing in accordance with the interim process and methods statement. This briefing includes the most relevant or best available published evidence relating to the clinical effectiveness of the technology.
Further information about how the evidence for this briefing was selected is available on request by contacting mibs@nice.org.uk.
Published evidence
There are 5 studies summarised in this briefing, including a total of 906 individuals, selected as the most relevant and best quality evidence relating to the technology. There are several further studies reported in conference abstracts in Italy which cover similar evidence and are not included here. All studies discussed were observational and prospective. All studies refer to the microINR meter, without 'link' capability.
The clinical evidence and its strengths and limitations are summarised in the overall assessment of the evidence.
Overall assessment of the evidence
The evidence of the technology is of moderate methodological quality. All studies had comparators. Three used multi-site recruitment and 4 showed good size populations. No studies were done in the UK. Only 1 study reported on user friendliness of the device. Four studies were done by healthcare professionals, 1 study assessed self-management. The studies show some discrepancy in the accuracy and imprecision of the microINR meter in 2 studies. Larger studies with direct comparisons to point-of-care tests, showing self-testing and with representation of patient experience with long‑term outcomes, would be beneficial.
Refaai et al. (2020)
Intervention and comparators
microINR point-of-care system, ACL laboratory analyser and CoaguChek XS point-of-care system.
Key outcomes
The microINR results show adequate imprecision and accuracy to both ACL analyser and CoaguChek XS. Agreement for the combined international normalised ratio (INR) ranges was 96% against ACL (for the combined INR ranges of less than 2.0, 2.0 to 4.5, and at least 4.5 within the limits of ±0.4, ±20% and ±25%, respectively) and more than 96% against the CoaguChek XS for the same ranges. The microINR system's imprecision (repeatability) showed coefficient of variation of 5.03% for INR less than 2.0 and 4.68% for the therapeutic INR range 2.0 to 3.5.
Joubert et al. (2018)
Key outcomes
Comparison of microINR values to venous laboratory values measured on the Sysmex CS2100i analyser showed high levels of dosage concordance (93.8%) and expanded clinical agreement (95.7%) were found. Assessment of precision showed no significant differences between instruments and test chips (variation in sample means, F=0.07, p=0.9299 and F=0.22, p=0.8067 respectively). In a total of 390 tests, 11 (2.8%) instrument or test chip errors were seen, and 26 (6.7%) operator or patient errors were seen. No test failures were recorded.
Strengths and limitations
This study supports the accuracy and precision of microINR for use by healthcare professionals in monitoring warfarin. The study limitations highlighted the low number of instruments and test chip lots used to evaluate test chip variability, the low number of patients in a supratherapeutic range as well as the low number of patients with possible interfering factors. This study was funded by the company's scientific group.
Larsen et al. (2017)
Study size, design and location
Prospective study across 1 outpatient clinic and 2 primary healthcare centres in Norway (n=186).
Key outcomes
microINR imprecision, as measured against laboratory tests, was 6% in the outpatient clinic and 6.3% in the primary healthcare centres, which did not meet the quality goal needed for imprecision (less than or equal to 5.0%) defined by Scandinavian evaluation of laboratory equipment for primary healthcare (SKUP).
microINR accuracy fulfilled the SKUP quality goal in both outpatient clinic and primary healthcare centres. User friendliness of the operating manual was rated as intermediate, operation facilities were rated as unsatisfactory and time factors satisfactory.
van den Besselaar et al. (2015)
Intervention and comparators
microINR, the ProTime InRhythm system, the CoaguChek XS system and the InRatio2 system compared with international standard for thromboplastin rTF/09.
Key outcomes
INR differences were significantly different for all point-of-care systems compared with international standards, except for the CoaguChek XS. The microINR showed a bias of -10.9% and -16.2% (for INR values less than 2.5 and at least 2.5, respectively). The imprecision coefficient of variation in venous blood was 5.0% for the microINR and considered acceptable.
Strengths and limitations
The number of capillary blood determinations were done with samples from a single individual which is a limitation of the study and may explain the different coefficient of variation values between capillary and venous blood. iLine Microsystems highlighted to the author that the calibration parameters of the microINR test chips had been amended for the Dutch market before the study, so this did not reflect the parameters on the chips in the market and therefore the data results may misrepresent the publicly available device. This study was funded by Roche Diagnostics, a manufacturer of a competitor device (the CoaguChek).
Food and Drug Administration Home Use Approval study 2020
Study size, design and location
Prospective non-randomised multicentre user study of 117 individuals across 4 sites.
Intervention and comparators
The microINR meter compared with individual self-user, healthcare professional as well as laboratory-based INR analysis.
Key outcomes
Usability of the device was assessed by individuals at a mean score of 4.69 (where 1 is least favourable and 5 favourable usability). The accuracy of the measurements were assessed against both healthcare professional measurements and the reference laboratory method. Results obtained indicate that the microINR system patient self-testers are able to get results as accurate as those obtained by healthcare professionals using the microINR system.