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 lab results. The enzyme-linked immunosorbent assay (ELISA) method was used to provide DD values and thresholds. Values above 0.60 mg/SEU 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 due to a history of DVT or PE, 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 females (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/SEU, 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 workup 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.

Acute Pulmonary Thromboembolism: A Retrospective Study in a Nigerian Private Tertiary Hospital

“…[26] Although the Wells score is a subjective clinical tool of predicting VTE and PE, [26] the modified tool predicted PE in 61.3% of the cases in the present study which is similar to findings in other studies. [15,31] D-Dimer assay were suggestive of PE in only 32.3% of cases confirmed by CTPA. This low yield of D-Dimer assay is similar to the findings in another study.…”

Appropriate Use of Venous Imaging and Analysis of the D-Dimer/Clinical Probability Testing Paradigm in the Diagnosis and Location of Deep Venous Thrombosis

“…Accordingly, VDU can be safely omitted in those patients. 11,24,25 In a recent meta-analysis of 10,002 patients, researchers found that patients with a low Wells score (≤1) and negative DD had an extremely low probability (1.2%, 95% CI, 0.7–1.8%) of DVT. There were a couple of exceptions to this finding.…”

“…Somewhat expectedly, we found no DVT in the low WCP groups; however, other studies have reported a small percentage of DVT in this group. 24–27 It is possible that DD was used to rule in instead of rule out DVT. It was not abundantly clear why the DD and VDU were ordered for these low clinical probability patients.…”

Incidence of and risk factors for preoperative deep venous thrombosis in patients undergoing gastric cancer surgery

“…On the other hand, lower extremity venous ultrasonography has high sensitivity (93-96%) as well as high specificity (98-99%) for the diagnosis of DVT [6][7][8]. However, ultrasonography in all preoperative patients as a screening tool is considered to represent overuse of this diagnostic resource [17,18]. Appropriate use of the D-dimer assay limits the overuse and added cost of ultrasonography without a negative impact [17].…”

“…However, ultrasonography in all preoperative patients as a screening tool is considered to represent overuse of this diagnostic resource [17,18]. Appropriate use of the D-dimer assay limits the overuse and added cost of ultrasonography without a negative impact [17]. Therefore, we use the D-dimer assay in combination with ultrasonography at our hospital to screen patients for the existence of DVT preoperatively.…”