A needle hub and catheter assembly are disclosed herein. The needle hub includes an introducer needle having a lumen extending therethrough. A needle hub is coupled to a proximal end of the introducer needle. A flash chamber is removably coupled to the needle hub or the introducer needle. An interior of the flash chamber is in fluid communication with the lumen of the introducer needle when the flash chamber is coupled to the needle hub or the introducer needle. As such, the flash chamber can collect a sample of blood that can be accessed when the flash chamber is removed. In some instances, the blood can also be dispensed from the flash chamber into a test strip or other testing device.