Surface testing involves taking samples from household surfaces to find the amount of mold growth and spores deposited around the home. Samples are typically collected by swabbing or tape lifting. The sample is then examined in a laboratory. Like with air testing the results can vary because mold growth and spores aren’t spread evenly across surfaces in the home and can change over time. Unlike air testing though, surface tests can’t identify the exact concentration of mold spores in the air.