The bilirubin results shown in the table are obtained on a p…

The bilirubin results shown in the table are obtained on a patient  Day  Result  1 4.3 mg/dL  2 4.6 mg/dL 3 4.5 mg/dL 4 2.2 mg/dL 5 4.4 mg/dL 6 4,5 mg/dL Given that the controls are within range each day, what is the probable explanation for the result on day 4?