Guideline Development Group

Action Statement 6: COMMUNICATE THE LIKELIHOOD OF LE DVT AND RECOMMEND FURTHER MEDICAL TESTING .

Physical therapists should recommend further medical testing after the completion of the Wells’ Criteria for LE DVT prior to mobilization (Evidence quality: I; Recommendation strength: Strong)

Action Statement Profile

Aggregate Evidence Quality: Level I

Benefit: Risk stratification can ensure proper diagnostic testing is completed

Risk, Harm, Cost: None

Benefit-Harm Assessment: Preponderance of benefit over harm

Value Judgments: None

Intentional Vagueness: None

Role of Patient Preference: None

Exclusions: None

Summary of Evidence

Once the Wells’ Criteria for LE DVT is complete, medical testing can be ordered by the medical team to diagnose or rule out a LE DVT. The selection of which medical test is beyond the scope of physical therapy practice, but there is benefit in understanding why tests are selected and how results guide the diagnostic process. If a patient is classified as unlikely to have a LE DVT, then the overwhelming recommendation is for the medical team to order a D-dimer test over other more costly and invasive tools. ^{25, 30, 42, 68 69} Within the referenced clinical practice guidelines, the evidence is rated as level I with grade of A to B for the recommendation. D-dimer is a measure of the breakdown or degradation of cross-linked fibrin which increases in the presence of a thrombosis. In patients with a LE DVT- unlikely classification and a negative D-dimer, less than 1% have a LE DVT and studies report sensitivity in upper 90s to 100%.^70-72 These patients need no further testing and can be considered safe to mobilize.^{25, 30, 35, 42, 68}

While the D-dimer test has high sensitivity, it has poor specificity. A positive D-dimer test does not indicate a definite LE DVT. A range of conditions, such as older age, infections, burns, and heart failure can lead to an elevated D-dimer test and hospitalized individuals have a high rate of false positives when the D-dimer is used for a suspected LE DVT.⁷³ When a LE DVT- unlikely patient has a positive or high D-dimer level, further testing is necessary. Most guidelines recommend a Doppler Ultrasound to confirm a LE DVT.^{25, 42, 60, 69} There is some debate on the type of ultrasound that is ordered, but this is beyond the focus of these guidelines. If the ultrasound confirms a LE DVT, medical treatment should be initiated and mobilization postponed. If the ultrasound is negative, the patient is safe to mobilize.

A patient rated as LE DVT-likely should immediately undergo a Duplex ultrasound.^{25, 30, 60, 69} Individuals in the DVT-likely category will test positive on the D-dimer test, so D-dimer has little value. If the ultrasound is negative, the physical therapist should consider the patient safe to mobilize. If the ultrasound is positive the physical therapist should defer mobility until medical treatment has achieved therapeutic levels.

In summary the results of the Wells’ Criteria for LE DVT should guide the selection of medical testing. Following the results of the medical team, the physical therapist can then make a decision about when it is safe to mobilize the patient.