Diagnostic Challenge of d-dimer Negative Upper Extremity DVT

Abstract

Studies suggest D-Dimer has a high sensitivity with negative predictive value for upper extremity DVT (UEDVT). Sensitivity is around 92% with a negative predictive value of 98%. UEDVT is an uncommon presentation with an incidence rate of 4-10%. Risk factors for UEDVT include thrombophilia, central venous catheters, malignancy, pacemakers and upper limb surgery and/or immobilisation. The use of scoring systems for assessing UEDVT risk is less well known and therefore poorly utilised. A scoring system similar to a Wells' score, known as Constans criteria, is a 2 level scoring system developed and first published in 2008. The Criteria considers, venous material in-situ, localised pain, unilateral oedema and plausibility of alternative cause. Score interpretation; -1 to 0 points (low probability of UEDVT 12%), 1 point (intermediate probability 20%), 2 to 3 points (high probability 70%). Kleinjan, et al., sought further improved upon this scoring tool by incorporating D-dimer results in the stratification of intermediate risk patients, asserting that its use can safely and effectively exclude venous thrombosis of the upper extremity. This case series shows 2 patients diagnosed with UEDVT. both patients had a Constans score of 1 therefore prompting use of D-Dimer results to stratify risk. Irrespective of negative D-dimer results, ultrasound doppler scans where performed and appropriate treatment given. The authors of this case series reviewed the limitations/interference factors of HemosIL HS D-Dimer reagent, along with 2 other D-Dimer reagents and subsequently developed recommendations which may be useful in interpretation of D-Dimers in clinical practice. Additionally, recommendation for cautious intrepretation of D-Dimer results in conjunction the Constans scoring tool with scores of 1 or less