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Age-Specific Cutoffs for D-Dimer to Rule Out Pulmonary Embolus

March 18, 2014

Age-Specific Cutoffs for D-Dimer to Rule Out Pulmonary Embolus

  1. Daniel J. Pallin, MD, MPH

Using the patient's age to determine the “normal” d-dimer threshold reduced computed tomography scanning without loss of sensitivity.

  1. Daniel J. Pallin, MD, MPH

Measurement of plasma d-dimer allows pulmonary embolus (PE) to be ruled out when clinical suspicion is low or moderate, but interpretation is complicated by the fact that d-dimer levels rise normally with age. In a multicenter European study, investigators prospectively evaluated the accuracy of an age-adjusted d-dimer cutoff in 2898 patients with low or moderate clinical probability for PE.

For patients aged 50 and older, a d-dimer result was considered negative if it was less than age ×10; for younger patients, the cutoff was fixed at 500 µg/mL. Patients with a positive result underwent computed tomographic pulmonary angiography (CT-PA). All patients were followed for 3 months. The use of the age-adjusted cutoff resulted in a 12% absolute increase and a 41% relative increase in the proportion of negative d-dimer results. Of 331 patients 50 and older with d-dimer levels between 500 µg/mL and their age-adjusted cutoff, only one (0.3%) was found to have PE during follow-up.

Comment

This important study shows that customizing the cutoff for “normal” according to the patient's age can reduce the number of patients requiring CT-PA without sacrificing sensitivity. This study should prompt discussion with laboratory medicine personnel to change the reporting of d-dimer to reflect age-adjusted values.

  • Disclosures for Daniel J. Pallin, MD, MPH at time of publication Grant / research support Agency for Healthcare Research and Quality; Department of Defense; Massachusetts Coalition for the Prevention of Medical Errors; NIH

Citation(s):

Reader Comments (5)

Abid Ahmed, MRCP(UK) Physician, Internal Medicine, Sturgeon Community Hospital, St. Albert, Alberta

Pulmonary Embolism is one of the commonest clinical condition in hospital practice which is over diagnosed leading to unnecessary CT scan with PE protocol in number of cases. The criteria used by most Emergency Physician are Wells Score plus D-dimer. Unfortunately although a high clinical suspicion (Wells criteria > 4) is rational, the workup most of the physician rely on to corroborate their diagnosis is D-dimer which has more negative predictive value than when it is positive. In addition, the intermediate probability Wells score between 3-4 with positive d-dimer result in a diagnostic dilemma for most physicians.
The above age-specific cut-off would be a welcome deviation in the approach to making a diagnosis of PE. A more larger multi-centred study should be done to validate age specific cut-off of d-dimer. This would help not only physician working in hospital where resources for CT scan are present but more so be a great help to those in the periphery and in poor resource centres.
Finally as d-dimer per se has more negative predictive value the validation of age -specific cut-off should also be equally sensitive in ruling out PE.
This would definitely decrease the cost of PE workup and allay the anxiety of the treating physician in under or over diagnosing it.

Dr. V Kantariya MD Physician, Family Medicine/General Practice

OVERDIAGNOSIS and OVERTREATMENT in PE!
CHOOSING WISELY!

OMERELADIL HAMID Physician, Neurology, International University of Africa

The outcome might be far better if the results compined and cross tabulated with the clinical objective probability score of PE

Dana Killam, MD. Physician, Emergency Medicine, Accident and urgent Care Center ,Cape Coral Fl.

For those patient with age adjusted D-Dimer as described with low and perhaps moderate probability may go a long way in convincingly eliminating the possibility of Pulmonary emboli. However, one must consider the context and all aspects of the patient's presentation to R/O PE,DVT etc. If there a reasonable possibility of PE then V/Q and/ or CT pulmonary angiogram should be done in spite of a low or negative D-Dimer by any standards

Sami Hammadi Prof. Other Healthcare Professional, Endocrinology, Faculty of Medicine, Alex. &UQU-Egypt &KSA

In order to justify the age related D-dimer levels in old age, many exclusion criteria are required.

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