A collection fitting for sampling a fluid from a tissue site, the collection fitting comprising: a tee-fitting having a first arm, a second arm, and a third arm, a first lumen extending through the tee-fitting only from the first arm to the third arm, and a second lumen extending through the tee-fitting only from the second arm to the third arm, and a third lumen extending through the tee-fitting only from the first arm to the second arm; and a container union coupled to the third arm and comprising a valve, the valve comprising: a valve housing having a first end, a second end, and a passage, the first end coupled to the third arm so that the passage is in fluid communication with the lumens in the third arm; and a flap (338, 340) coupled to the second end of the valve housing and configured to selectively permit fluid communication through the second end, wherein the flap (338, 340) is coupled to a biasing member (342, 344) configured to bias the flap (338, 340) to a closed position, and in that the collection fitting further comprises an actuator having at least one rod (348, 350) configured to engage the flap (338, 340) to move the flap (338, 340) to an open position, the actuator configured to be coupled to a specimen container, and characterised in that the third lumen is a path of fluid communication that is unaffected by sampling the fluid from the tissue site. a tee-fitting having a first arm, a second arm, and a third arm, a first lumen extending through the tee-fitting only from the first arm to the third arm, and a second lumen extending through the tee-fitting only from the second arm to the third arm, and a third lumen extending through the tee-fitting only from the first arm to the second arm; and a container union coupled to the third arm and comprising a valve, the valve comprising: a valve housing having a first end, a second end, and a passage, the first end coupled to the third arm so that the passage is in fluid communication with the lumens in the third arm; and a flap (338, 340) coupled to the second end of the valve housing and configured to selectively permit fluid communication through the second end, wherein the flap (338, 340) is coupled to a biasing member (342, 344) configured to bias the flap (338, 340) to a closed position, and in that the collection fitting further comprises an actuator having at least one rod (348, 350) configured to engage the flap (338, 340) to move the flap (338, 340) to an open position, the actuator configured to be coupled to a specimen container, and characterised in that the third lumen is a path of fluid communication that is unaffected by sampling the fluid from the tissue site. a valve housing having a first end, a second end, and a passage, the first end coupled to the third arm so that the passage is in fluid communication with the lumens in the third arm; and a flap (338, 340) coupled to the second end of the valve housing and configured to selectively permit fluid communication through the second end, wherein the flap (338, 340) is coupled to a biasing member (342, 344) configured to bias the flap (338, 340) to a closed position, and in that the collection fitting further comprises an actuator having at least one rod (348, 350) configured to engage the flap (338, 340) to move the flap (338, 340) to an open position, the actuator configured to be coupled to a specimen container, and characterised in that the third lumen is a path of fluid communication that is unaffected by sampling the fluid from the tissue site.