What does an abnormal albumin lab value mean?

Serum protein. Albumen is a protein in the blood. It is an indicator of your nutritional status. The albumen in the blood does many things. It binds to many chemicals and certain medications and is a transport mechanism for many body chemicals and functions. It can be low with nutritional states and with certain illnesses like kidney disease. It is manufactured in the liver. Liver disease will alter levels.
Usually low level. Means that the liver does not make Albumin enough. Causes are many, including liver failure, infection, malnutrition, or simply a patient who was in hospital with a severe illness and now back to home and beginning to recuperate. Other causes exist but rare including cancer. Your physician is able to correlate your low Albumin to your exact condition.