Let me try to break down the concept of pooled testing

Pooled testing is a procedure commonly used to reduce the cost of screening a large number of individuals for infectious diseases.

In its simplest form, pooled testing works by compositing a set of individual specimens (e.g., blood or urine) into a common pool.

If the pool tests negative, all individuals within it are diagnosed as negative. If the pool tests positive, retesting is needed to decode the positive individuals from the negative individuals.

Traditionally, pooled testing has assumed that each individual has the same probability of being positive. However, this assumption is often unrealistic, especially when known risk factors can be used to measure distinct probabilities of positivity for each individual.