CHI said their medical laboratories won't be running like normal.
Parents have been warned about strike action that will affect Ireland's children's hospitals today.
The Medical Laboratory Scientists Association is taking industrial action.
The strike will take place today, May 24th, and tomorrow, May 25th.
Children's Health Ireland has told parents to expect delays.
In a statement, CHI said their medical laboratories won't be running like normal.
"The testing of bloods and other tests will not be widely available at our hospitals."
Hospitals affected include Connolly, Crumlin, Tallaght, and Temple Street too.
It is believed the strike will run from 8 am to 8 pm each day.
"The strike will impact all areas of scheduled care including outpatients, inpatients, and day cases."
However, the hospital will facilitate time-sensitive and critical testing. Emergency and impatient cases will be prioritised at this time.
"Patients should attend their appointments as normal unless they are contacted directly by their hospital."
Parents can still bring children to A&E if they require urgent medical care.
Officials stated that there will be delays, but they are still seeing patients.
However, patients who don't need urgent treatment will likely experience delays.
Anyone with minor medical concerns should contact their GP or pharmacist.
"There will be impacts on services during this strike but we urge parents to bring their children to their nearest Emergency Department or Urgent Care Centre if they need Emergency or Urgent Care."
MSLA also took strike action last week on May 18th.
They are calling for equal pay for lab workers.
They have previously called for pay parity for their staff.
