The COVID-19 pandemic has placed healthcare resources around the world under immense pressure. South Africa, given the condition of its
healthcare system, is particularly vulnerable. There has been much discussion around rational healthcare utilisation, ranging from diagnostic
testing and personal protective equipment to triage and appropriate use of ventilation strategies. There has, however, been little guidance around
use of laboratory tests once COVID-19 positive patients have been admitted to hospital. We present a working guide to rational laboratory test
use, specifically for COVID-19, among hospitalised patients, including the critically ill. The specific tests, the reasons for testing, their clinical
usefulness, timing and frequency are addressed. We also provide a discussion around evidence for the use of these tests from a clinical perspective.