CMPA is a clinical diagnosis, not typically identified by a single blood or stool test. Common symptoms include gastrointestinal issues like blood or mucus in the stool, gas, frequent spit-ups or vomiting, and reflux. Other signs can include respiratory issues such as frequent runny nose or cough, and skin reactions like eczema, dry itchy skin, or hives. Persistent colic, excessive crying, irritability, and poor weight gain or appetite can also be indicative of CMPA.