Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
The blood tests that truly reflect liver function are the following; normal values listed are for adult men - women and children have similar but slightly different ranges of normal test values
Coagulation panel (prothrombin time or PT, and international
normalized ratio or INR): These tests measure blood's ability for normal
clotting and prevention of bleeding and
bruising. This is the function of
certain proteins called clotting factors that normally are produced in the liver. Normal values are about 9.5 to 13.8 seconds.
Albumin level (hypoalbuminemia): Albumin is a very common protein
found in the blood with a variety of functions. It also is produced only in
the liver, and if its levels are lower than normal it can be suggestive of
chronic liver disease or liver cirrhosis. Of note, many conditions other
than liver disease also may cause low albumin
levels. Normal values are about 3.5 to 5 g/dL.
Bilirubin: This molecule is a byproduct of the routine destruction of red blood
cells occurring in the liver. It is normally released as bile in the feces. Elevation of
the bilirubin can suggest liver dysfunction. However, other conditions with
increased destruction of red blood cells also can cause elevated bilirubin
levels despite normal liver function. Normal values are about 0.1 to 1.0 mg/dL.
Platelet count: Low platelet count (thrombocytopenia) has many causes,
one of which can be advanced liver disease. Normal platelet counts are about 150,000 to 400,000 per microliter (mcL).
Glucose: Glucose level is maintained in the body by a variety of mechanisms. The liver can release glucose in the blood for nourishment of other cells in case of starvation with insufficient oral intake of glucose. This process, called gluconeogenesis, is another major function of the liver. In advanced liver disease, this function of the liver can be compromised leading to unusually low glucose levels in the absence of adequate oral intake.
Conversely, a large number of people with liver cirrhosis become glucose intolerant and develop diabetes.
GGT (Gamma-glutamyl transpeptidase): This enzyme is thought to indicate possible liver damage; the higher the abnormal level, the more likely there is liver damage. Normal levels of GGT are about 9 to 48 U/L.
ALP (alkaline phosphatase): The liver synthesizes the highest amounts of this enzyme so high levels in the blood may suggest liver injury among other causes. Normal levels of ALP are about 45 to 115 U/L.
LD or LDH
(Lactate dehydrogenase): This enzyme may be elevated in many types of diseases, including liver disease. Normal levels are about 122 to 222U/L.
Note that many hospitals and doctor's offices list a liver function panel as part of a lab workup. These panels vary and may consist of AST, ALT and some or all of the tests listed above. In addition, the normal panel values may vary somewhat, especially between adult men, women and children so viewing the
"normal" ranges of test values is always recommended. In addition, some clinicians recommend other tests such as serum ammonia and serum lactate levels in their panels.