LabCorp permits same-day appointments provided they are booked at least two hours in advance, states the LabCorp website. It's possible to book these online using the same website.
Appointments are not required, but LabCorp locations are typically busiest in the mornings from the time they open until 10 a.m., states the LabCorp website. If you do schedule an appointment, it is recommended that you do so outside this time frame. You can schedule all appointments online through the LabCorp website. Some tests, such as paternity tests, require payment to be made in advance and pre-authorization, so be sure to take that into consideration before scheduling your appointment.