Pulmonary embolism (PE) is a potentially severe diagnosis with high short-term mortality. Recently, age-adjusted cut-off values (age × 10 μg/l) of D-dimer were introduced to improve the diagnostic workup in older patients. In clinical practice, PE is considered ‘ruled out’ in patients with a non–high clinical probability and a normal D-dimer. However, all diagnostic tests have a small false-negative rate. This small probability of misdiagnosis might be easily overlooked by clinicians when using simplified dichotomized flow charts. This case illustrates a normal D-dimer (age-adjusted) but with a PE. We recommend clinicians using the D-dimer test—either conventional or age-adjusted in a rule-out strategy to be aware of the—albeit small probability of a false-negative result.