Temperature above 37ºC but below 38ºC for 24h. If it exceeds 38ºC, and are no specific medical indications, this should be reported to a healthcare professional, as well as if it recurs for some days at approximately the same time.
In the case of hematological patients, it is important that your doctor is aware of the situation, especially when it occurs following any proceedings or chemotherapy treatment, so action can be taken promptly.