A number of children and parents who visited the Juliana Kinderziekenhuis must be tested for tuberculoses.
The reason for the testing is because a worker at the hospital has been infected with the disease.
Roughly 500 parents received a letter to come back to the hospital for tests conducted by the Municipal Health Service (GGD).
Juliana Kinderziekenhuis says children who visited the hospital between August 6 and October 25 were in danger of being exposed to the disease from the worker.
On Thursday, 300 hospital workers will be tested for the disease.
Tuberculoses is an extremely infectious disease transmitted by bacteria through coughing and sneezing.
One in three people are usually infected if they come into contact, but most people do not develop symptoms.
The infected staff member has been placed on sick leave.