Exploring Patterns of D-Dimer Assay Ordering at an Australian Rural Referral Hospital: A Retrospective Audit.

The majority of investigation sequences followed the guideline-recommended order of testing for PE diagnosis.

• 79.2% of cases followed the guideline-recommended investigation sequence
• A total of 245 D-dimer results were included in the audit
• Data were collected from Dubbo Health Service over a 12-month period (1 January to 31 December 2024)
• Results were categorised according to alignment with guideline-recommended investigation sequence

The diagnostic yield of CTPA among patients who underwent D-dimer testing was low.

• The diagnostic yield of CTPA among patients who underwent D-dimer testing was 4.9%
• This finding is consistent with published reports of increasing utilisation of D-dimer testing and CTPA
• 245 D-dimer results were included, comprising 119 positive and 126 negative results

D-dimer results were nearly evenly split between positive and negative results.

• Of 245 total D-dimer results, 119 were positive and 126 were negative
• Positive results represented approximately 48.6% of all results
• Negative results represented approximately 51.4% of all results

Discordant investigation pathways most commonly involved positive D-dimer results without subsequent CTPA, or CTPA performed despite a negative D-dimer.

• 20.8% of cases did not follow the guideline-recommended investigation sequence
• Two main types of discordant pathways were identified: positive D-dimer without subsequent CTPA, and CTPA performed despite a negative D-dimer
• These discordant pathways may limit the clinical usefulness of the test in some cases

Ordering patterns at Dubbo Health Service were broadly consistent with published reports of increasing utilisation of D-dimer testing and CTPA.

• The study was conducted at a rural referral hospital (Dubbo Health Service) in Australia
• The retrospective audit covered the full calendar year of 2024
• The findings align with broader trends of increasing test utilisation reported in the literature

Improved documentation of pre-test probability and targeted education were identified as potential strategies to enhance D-dimer integration into diagnostic workflows.

• Improved documentation of pre-test probability was recommended
• Targeted education regarding appropriate test selection and interpretation was suggested
• These measures may enhance the integration of D-dimer testing into diagnostic workflows for PE