Sirs: We would like to thank Dr. Wiwanitkit for his interest in our manuscript [1]. We agree that markers in heart failure like NT-proBNP and galectin-3 may be influenced by thyroid dysfunction [2]. In the diagnostic work-up in patients with heart failure thyroid function tests are routinely measured as advised by the European Society of Cardiology [3]. Before entering the DEAL-HF study, patients were extensively screened and tested according to this guideline. Patients with untreated thyroid disease were ineligible for participation in the trial. In addition, also patients with an active malignant disease were excluded [4]. During follow-up, 98 patients died. The majority of patients died from a cardiovascular cause, including 42 from worsening heart failure and 36 from sudden cardiac death. Twenty patients died from a non-cardiovascular cause. The median galectin-3 levels did not differ between the three groups (p = 0.54).

We do agree that laboratory quality control is an important issue and that interference in sample collection and laboratory analysis should be avoided. Laboratories involved in our study have international quality certificates.