Hi,

I have an excel sheet of patients. Column A contains a list of cases and contacts. Column B has the identification number of each case and contact. Some cases have contacts linked to them some cases don't have contacts linked. Each case has a unique identification number but contacts have same Identification number as the case they are linked to or exposed to with the C1 or C2 or C3 because those cases that have contacts must have 3 contacts linked to them. So if the unique identification number of the first case in the line list is ZZE-23_001, then the unique identification of the second case is ZZE-23-002. If this second case has contacts linked to it then the unique identification numbers of the 3 contacts linked to this second case are ZZE-23_002C1, ZZE-23-002C2, and ZZE-23-002C3 respectively for the first, second, and third contacts. Column C has the results of the cases and their contacts. The results are either Positive , Intermediate or negative. Column D contains the date of onset of symptoms of cases only. The contacts do not have the date of onset, as they are not sick or are not patients. Hence, in Column D the cells are blank for the contacts but have dates of onset for cases. The rule is that if a case has a positive or intermediate result in Column C then the patient should return for follow-up 60 days from the date of onset. If a contact has a positive or intermediate result then the case that has the contact or linked to the contact should return for follow up not the contact even if the result of that case linked to that contact is negative. How do I calculate the date of follow-up in power query, if a case has a Positive or Intermediate result or if a case has a a  contact with a Positive or Intermediate result.