Method for carrying out an integrity test on a double filter capsule, which method comprises: - providing the double filter capsule, which has a housing in which a first filter and a second filter are arranged one downstream of the other in a flow direction of a medium to be filtered such that, during a filtration process, the medium to be filtered flows in its flow direction from an upstream chamber in the housing, through the first filter into an intermediate chamber between the first filter and the second filter, and onward through the second filter to an outlet, the housing having an upstream-chamber access point for feeding a test fluid into the upstream chamber and an intermediate-chamber access point for feeding the test fluid into the intermediate chamber; - providing a connecting line between the upstream-chamber access point and the intermediate-chamber access point for fluidic connection between the upstream chamber and the intermediate chamber, at least the fluidic connection toward the intermediate chamber being closable; - determining the state of integrity of the double filter capsule on the basis of at least the following two test phases: -- a first test phase, which comprises: feeding the test fluid into the upstream chamber while the fluidic connection of the connecting line toward the intermediate chamber is closed, and carrying out a first integrity test; and -- a second test phase, which comprises: simultaneously feeding the test fluid into the upstream chamber and via the intermediate-chamber access point into the intermediate chamber while the upstream chamber is fluidically connected to the intermediate chamber via the connecting line such that pressure equalization takes place between the upstream chamber and the intermediate chamber, and carrying out a second integrity test. - providing the double filter capsule, which has a housing in which a first filter and a second filter are arranged one downstream of the other in a flow direction of a medium to be filtered such that, during a filtration process, the medium to be filtered flows in its flow direction from an upstream chamber in the housing, through the first filter into an intermediate chamber between the first filter and the second filter, and onward through the second filter to an outlet, the housing having an upstream-chamber access point for feeding a test fluid into the upstream chamber and an intermediate-chamber access point for feeding the test fluid into the intermediate chamber; - providing a connecting line between the upstream-chamber access point and the intermediate-chamber access point for fluidic connection between the upstream chamber and the intermediate chamber, at least the fluidic connection toward the intermediate chamber being closable; - determining the state of integrity of the double filter capsule on the basis of at least the following two test phases: -- a first test phase, which comprises: feeding the test fluid into the upstream chamber while the fluidic connection of the connecting line toward the intermediate chamber is closed, and carrying out a first integrity test; and -- a second test phase, which comprises: simultaneously feeding the test fluid into the upstream chamber and via the intermediate-chamber access point into the intermediate chamber while the upstream chamber is fluidically connected to the intermediate chamber via the connecting line such that pressure equalization takes place between the upstream chamber and the intermediate chamber, and carrying out a second integrity test. -- a first test phase, which comprises: feeding the test fluid into the upstream chamber while the fluidic connection of the connecting line toward the intermediate chamber is closed, and carrying out a first integrity test; and -- a second test phase, which comprises: simultaneously feeding the test fluid into the upstream chamber and via the intermediate-chamber access point into the intermediate chamber while the upstream chamber is fluidically connected to the intermediate chamber via the connecting line such that pressure equalization takes place between the upstream chamber and the intermediate chamber, and carrying out a second integrity test.