Vitamin D point-of-care testing

Abstract

Growing recognition of the multifaceted role of Vitamin D has augmented the demand for Vitamin D testing through swift, yet reliable, point-of-care testing (POCT) methods, unveiling a niche for development of a novel pharmacist-led service. The aim was to establish a framework for pharmacist-led Vitamin D POCT in primary care. The objectives were to: 1) Review available Vitamin D POCT, 2) Validate the Vitamin D POCT versus the gold standard, 3) Develop and validate a framework for Vitamin D POCT and 4) Assess the feasibility of the pharmacist-led framework within community pharmacy. The method consisted of: 1) Appraisal of Vitamin D POCT, 2) Validation of a Vitamin D POCT kit by comparing laboratory test results from Mater Dei Hospital (gold standard) with POCT results (20 patients), 3) Development and validation of a framework for pharmacist-led Vitamin D POCT, consisting of a Data Collection Sheet, Standard Operating Procedure and Action Plan and 4) Assessment of the feasibility of the developed framework (80 participants) within a community pharmacy setting. 1) Seven Vitamin D POCT kits were compared, 3 of which are available locally. The test kits use chromatographic immunoassay techniques providing quantitative (n=4) or semiquantitative (n=3) results. The test selected for use in this study was the semi-quantitative AcroBiotech Inc. Vitamin D Rapid Test Cassette with a sensitivity of 4ng/ml and a cost of €6 per kit. 2) Concordance between the two methodologies was observed when the POCT kit was validated against the MDH lab value (κ = 0.84, p-value <0.001). 3) The Data Collection Sheet involves assessment of risk factors associated with development of Vitamin D deficiency. The Action Plan provides recommendation on maintaining adequate Vitamin D levels to patients through an Information Leaflet in English and Maltese and guidance on supplementation to prescribers, as necessary. A Referral Note is used to refer patients to prescribers when Vitamin D deficiency is identified, for symptomatic patients or patients at high risk of developing Vitamin D deficiency. 4) Feasibility testing of the Vitamin D POCT framework within a community pharmacy setting was carried out on 80 participants, 8 participants having deficient and 49 participants insufficient Vitamin D levels. Significant association was observed between participant perception that Vitamin D levels have an important impact on general health with sun exposure (p = 0.034). Participants who suffer from chronic conditions are more likely to have their Vitamin D levels tested (p = 0.042), those suffering from metabolic disorders being more likely to have deficient/insufficient levels of Vitamin D (p = 0.026). Participants who had their Vitamin D levels tested are more likely to be prescribed Vitamin D supplementation (p <0.001), to which they are adherent (p <0.001). Concurrent consumption of Vitamin D when taking other medication/supplementation was observed (p <0.001). The review identified a POCT kit that could be used within a framework for community pharmacist-led assessment of Vitamin D within the context of collaborative care. Despite the study being carried out within a Mediterranean climate, a high incidence of Vitamin D deficiency/insufficiency was observed, indicating the value of providing access to this service. A pharmacist-led service would support patients who require referral, access to testing and early detection of Vitamin D deficiency/insufficiency.