Response to the Comment: “Advocating prudent D-dimer testing: constructive perspectives and comments on “How we manage a high D-dimer””

We would like to thank Gonzaga and de Alencas for their letter. Their comments on our review article “How we manage a high D-dimer” recently published in Haema-tologica¹ are reasonable and well circumstantiated. The main objective of our review was to simplify the particularly complex topic of increased D-dimer levels in order to provide a handy tool for the daily clinical practice of hematologists. The authors made two comments to our narrative review. We agree with Gonzaga and de Alencas’s first comment that D-dimer may carry a high positive predictive value in selected pathological conditions characterized by a very high pre-test probability.² However, in our review we referred (always for reasons of practicality) to the main clinical setting for which the D-dimer is used which is pulmonary embolism exclusion. In this setting, to ensure optimal patient management, an ideal D-dimer test should have very high sensitivity and a very high negative predictive value.³

Regarding the second comment on the inappropriateness and overuse of the D-dimer test in most cases, we also agree with the authors. Unfortunately, the D-dimer test has become very common practice, at least in Italy, and its use has exponentially increased over the last few years (hence the nickname “D-dimeritis”), particularly during the COVID-19 pandemic.⁴ It is clear, however, that an elevated D-dimer in an individual referred by the general practitioner to the hematologist cannot be ignored, but all the diagnostic procedures listed in Figure 3 of our review¹ have to be implemented to rule out or diagnose the possible underlying conditions associated with an increased D-di-mer. We agree that educating general practitioners on the appropriateness of prescribing D-dimer tests is needed, but that would lead only to a mid- to long-term response.