Age-Adjusted D-Dimer and CTPA use in Suspected Pulmonary Embolism

• Research type

  Research Study

• Full title

  Impact of Age-Adjusted D-dimer Thresholds on CTPA Utilization and Diagnostic Yield in Suspected Pulmonary Embolism: A Retrospective Cohort Study

• IRAS ID

  372682

• Contact name

  Shoaib Asghar

• Contact email

  Shoaib.Asghar@bedsft.nhs.uk

• Sponsor organisation

  Bedfordshire Hospitals NHS FT (Luton & Dunstable Site)

• Clinicaltrials.gov Identifier

  26/PR/0623, PR Committee

• Duration of Study in the UK

  0 years, 7 months, 24 days

• Research summary

  This retrospective observational cohort study aims to evaluate the impact of age-adjusted D-dimer thresholds on CT pulmonary angiography (CTPA) utilization and diagnostic yield in adult patients investigated for suspected Pulmonary Embolism at Luton & Dunstable University NHS Hospital.

  D-dimer testing is routinely used to guide investigation of suspected pulmonary embolism; however, D-dimer levels increase physiologically with age, reducing specificity and potentially leading to unnecessary CTPA imaging in older adults. Age-adjusted D-dimer thresholds may safely reduce unnecessary imaging while maintaining diagnostic accuracy.

  The study will retrospectively review routinely collected clinical data from adult patients who underwent D-dimer testing with or without CTPA during the study period. Patients will be assessed using both the standard D-dimer threshold currently used in clinical practice and an age-adjusted threshold approach (age × 10 ng/mL for patients aged >50 years).

  Primary outcomes will include:
  - CTPA utilization rates
  - Diagnostic yield of CTPA

  Secondary outcomes will include:
  - Potentially avoidable imaging
  - Missed pulmonary embolism diagnoses on follow-up

  Data will be extracted from Nervecentre electronic patient records, ICE laboratory systems, and PACS radiology systems. No patient contact or intervention is involved. Data will be pseudonymized during collection and anonymized prior to analysis in accordance with UK GDPR and local NHS information governance policies.

• REC name

  North East - Newcastle & North Tyneside 2 Research Ethics Committee

• REC reference

  26/NE/0103

• Date of REC Opinion

  26 May 2026

• REC opinion

  Favourable Opinion