title: Appropriate use of D-dimer testing can minimize over-utilization of venous duplex ultrasound in a contemporary high-volume hospital.
abstract: BACKGROUND
  The sensitivity of d-dimer (DD) in detecting deep venous thrombosis (DVT) is remarkably high; however, many institutions send patients immediately for a venous duplex ultrasound (VDU). This study was designed to examine the appropriate utilization of DD and VDU in a high-volume hospital.
  
  
  METHODS
  A retrospective study was conducted on consecutive patients who presented to a high-volume emergency department (ED) with lower extremity limb swelling/pain over a 30-day period, who were sent for VDU during an evaluation for DVT. VDU data were merged with electronic DD laboratory results. The enzyme-linked immunosorbent assay method was used to provide DD values and thresholds. Values above 0.60 mg/fibrinogen equivalent unit (FEU) were considered abnormal.
  
  
  RESULTS
  We reviewed the medical records of 517 ED patients in the month of June 2013. After applying the Wells criteria, 157 patients (30.4%) were excluded because of a history of DVT or pulmonary embolism, having been screened for shortness of breath, or sent for surveillance-leaving 360 for analysis. The average age was 59.3 ± 16.5 years with more women (210, 58.3%) and the majority reported limb pain or swelling (73.9%). DD was performed on 51 patients with an average value of 3.6 ± 5.4 mg/FEU, of which 43 (84.3%) were positive. DD identified all positive and negative DVT patients (100% sensitivity and negative predictive value), but also included 40 false positives (16.7% specificity). On the other hand, 309 patients were sent directly to VDU without DD; of those, 43 (13.9%) were positive for DVT. However, 266 (86.1%) patients were negative for DVT by VDU without DD and these were deemed improper by our current study protocol. Potential charge savings were calculated as VDU for all (360 × $1000 = $360,000), DD for all (360 × $145 = $52,200), and VDU for both true and false positives (estimated to be about 25% of the cases; 90 × $1000 = $90,000); this equals a charge savings of $217,800 and would avoid unnecessary VDUs.
  
  
  CONCLUSIONS
  Based on the results of our study, we suggest that the DD test be utilized during the initial work-up for patients with limb swelling/pain in the emergency room. Appropriate utilization of DD, as well as other clinical criteria, may limit the over-utilization and added cost of VDU, without a negative impact on patient care. The results of DD tests should be utilized to limit the number of patients sent for VDU to only those patients with a positive DD or other significant underlying concerns.
authors.affiliation: Department of Surgery, Robert C. Byrd Health Sciences Center, West Virginia University, Charleston, WV. Electronic address: amousa@hsc.wvu.edu.
authors.forename: Albeir Y
authors.initials: AY
authors.lastname: Mousa
authors.affiliation: CAMC Health Education and Research Institute, Charleston, WV.
authors.forename: Mike
authors.initials: M
authors.lastname: Broce
authors.affiliation: Department of Surgery, Robert C. Byrd Health Sciences Center, West Virginia University, Charleston, WV.
authors.forename: Gurpreet
authors.initials: G
authors.lastname: Gill
authors.affiliation: CAMC Health Education and Research Institute, Charleston, WV.
authors.forename: Maher
authors.initials: M
authors.lastname: Kali
authors.affiliation: Department of Surgery, Robert C. Byrd Health Sciences Center, West Virginia University, Charleston, WV.
authors.forename: Michael
authors.initials: M
authors.lastname: Yacoub
authors.affiliation: Department of Surgery, Robert C. Byrd Health Sciences Center, West Virginia University, Charleston, WV.
authors.forename: Ali F
authors.initials: AF
authors.lastname: AbuRahma
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D017046:Cost Savings; D003362:Cost-Benefit Analysis; D057286:Electronic Health Records; D004797:Enzyme-Linked Immunosorbent Assay / Q000191:economics / Q000706:statistics & numerical data*; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D017721:Hospital Costs; D061847:Hospitals, High-Volume; D006801:Humans; D035002:Lower Extremity / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians' / Q000191:economics; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D018616:Ultrasonography, Doppler, Duplex / Q000191:economics / Q000706:statistics & numerical data*; D019564:Unnecessary Procedures / Q000191:economics / Q000706:statistics & numerical data*; D020246:Venous Thrombosis / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000191:economics
chemical_list: D015415:Biomarkers; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D