Is d-dimer point of care testing practical in primary care?

On the surface, d-dimer point of care testing seems cost effective and convenient but will general practitioners use this technology? Qualitative point of care tests require a capillary blood sample and a positive result produces a pink line on a reagent strip, similar to urinary pregnancy tests. This can be difficult for users to interpret1, whilst also being less sensitive2 than quantitative point of care tests. Quantitative testing requires additional apparatus, calibration, greater volumes of blood for sampling and can take up to 15 minutes to process. Compounded by an environment of increasing complaints against doctors and litigation, GPs may decide to err on the side of caution and refer patients with a suspected PE to hospital.

Could a PE pathway spanning primary and secondary care be a more appropriate solution? Clinically stable patients with a potential PE could be initiated on anticoagulation in primary care and referred to a rapid access clinic (seen within 24 hours) for further assessment including CTPA if required. This would reduce the strain placed on emergency departments, avoid unnecessary hospital admissions and reduce the frustration experienced by patients who would otherwise be waiting for investigations in hospital.

1. Geersing G, Toll D, Janssen K, Oudega R, Blikman M, Wijland R, et al. Diagnostic Accuracy and User-Friendliness of 5 Point-of-Care D-Dimer Tests for the Exclusion of Deep Vein Thrombosis. Clinical Chemistry 2010;56:1758-1766.

2. Geersing G, Janssen K, Oudega R, Bax L, Hoes A, Reitsma J, Moons K. Excluding venous thromboembolism using point of care D-dimer tests in outpatients: a diagnostic meta-analysis. BMJ 2009;339:b2990.

Competing interests: None declared