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D-dimer testing for DVT is a game-changer in ambulatory care

Point of care tests for patients with suspected deep vein thrombosis have reduced waiting times by up to 75%

Point of care tests for patients with suspected deep vein thrombosis have reduced waiting times by up to 75%

D-dimer
Testing for D-dimer. Picture: iStock

 

The Great Western Hospital, Swindon, ambulatory care unit (ACU) has introduced point of care testing (POCT) for D-dimer in the assessment of patients presenting with suspected lower limb deep vein thrombosis (DVT). 

D-dimer is a degradation product formed by the breakdown of fibrin, and is widely used as a diagnostic aid in low and moderate-risk patients with suspected DVT (Perveen et al 2013).

In 2017, the local community DVT service closed and the ACU took over provision of the service. But staff raised concerns about the increase in workload in an already busy department where the wait for a laboratory D-dimer result could be in excess of two hours.

The team therefore decided that POCT would provide the ACU with increased capability to manage this cohort of patients and help enable rapid exclusion of DVT.

POCT involves analytical procedures performed by healthcare professionals outside the conventional laboratory (Institute of Biomedical Science (IBMS) 2017).

At the Great Western Hospital, there has been effective use of blood gas analysers in areas such as the emergency department, the acute assessment unit and intensive care, and this type of POCT analysis is a useful tool for diagnosis monitoring.

It is also an aid in management (Singh et al 2013) and can be found throughout NHS hospitals. Correct POCT can result in rapid and easy bedside interpretation (Singh et al 2013), which is clearly a benefit to patients. 

Successful trial

A POCT D-dimer analyser has been trialled successfully on the ACU, and patient safety and accurate diagnostic capability were important considerations.

Geersing et al (2010) assessed five POCT D-dimer analysers and concluded that they demonstrated good diagnostic accuracy, similar to that in laboratory testing.

POCT results from the ACU were compared with Great Western Hospital laboratory testing and no significant concerns were raised.

However, clinicians must be aware that with any D-dimer test, either POCT or laboratory, the result should be used only in combination with an effective clinical assessment (Geersing et al 2010). 

Crucially, part of the success of POCT depends on the training of staff because obtaining a correct specimen is vital (IBMS 2017). All staff involved in obtaining blood samples must therefore be properly trained to ensure use of the new technology is embedded in practice. 

Reduced waiting times

The D-dimer analyser can provide a result in 20 minutes, leading to a much shorter patient length of stay. Instead of waiting more than two hours, patients can be assessed and discharged quickly. Some remain in the ACU for only 30 minutes.

Rapid diagnostic testing has therefore reduced waiting times, and enabled quicker diagnosis and a better patient experience.

On a busy unit, this not only improves patient flow but also provides increased capacity to assess other patients. For a hospital laboratory, it means fewer samples to process.

The D-dimer analyser is now being used successfully to assist with the assessment of patients presenting with suspected pulmonary embolism.

It is hoped the effectiveness of this test to reduce waiting times, reduce length of stay, support rapid diagnosis and improve patient flow will be the catalyst for further expansion of POCT on the ACU.

References

  • Geersing G, Toll D, Janssen K et al (2010) Diagnostic accuracy and user-friendliness of 5 point-of-care D-dimer tests for the exclusion of deep vein thrombosis. Clinical Chemistry. 56, 11, 1758-1766.
  • Institute of Biomedical Science (2017) Point of Care Testing (Near-Patient Testing) Guidance on the Involvement of the Clinical Laboratory. IBMS, London.
  • Singh V, Khatana S, Gupta P (2013) Blood gas analysis for bedside diagnosis. National Journal of Maxillofacial Surgery. 4, 2, 136-141.
  • Perveen S, Unwin D, Shetty A (2013) Point of care D-dimer testing in the emergency department: a bioequivalence study. Annals of Laboratory Medicine. 33, 1, 34-36.

About the author

Neal_Aplin

Neal Scott Aplin is an advanced nurse practitioner at Great Western Hospitals NHS Foundation Trust

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