Liver and Pancreas

vital liver functions

synthesis, storage, metabolism, clearance

protein synthesis liver tests

albumin, prealbumin, PT/INR

cholestasis liver tests

bilirubin, ALP, 5’-nucleotidase, GGT

heptocellular injury liver test

AST, ALT

detoxification liver test

ammonia

albumin normal range

4-5

hypoalbuminemia is asymptomatic until

<2-2.5

prealbumin normal range

17-34

prealbumin is best test to assess

protein calorie nutrition, used in pts receiving TPN

albumin serum half-life

20 days

prealbumin serum half-life

2 days, smaller body pool

PT/INR normal range

PT: 12.7-15.4 sec, INR: 0.9-1.1

clotting factors require activation with

vitamin K

when prolonged PT normalizes after vit K

malabsorption, malnutrition, warfarin, antibiotics

prolonged PT remains prolonged after vit K

liver failure, inherited clotting factor deficiency

PT/INR in liver disease provides

prognostic data

liver impairment needed to see clotting abnormalities

>80% loss of synthetic function

PT/INR has clinical relevance with

bleeding risk

cholestasis

deficiency of excretory function of liver

intrahepatic cholestasis

interference with bile secretion

extrahepatic cholestasis

obstruction of large bile duct, usually from stones

jaundice

increased bilirubin

pruritus

increased bile salts

xanthomas

increased deposit of lipids in skin

excretory liver function tests do not

distinguish between intra and extrahepatic cholestasis

alkaline phosphate (ALP) normal range

33-96

ALP concentrations >4x normal

cholestasis, Paget disease, infiltrative liver disease

concentration 3x times normal or less

all types of liver disease

5’-Nucleotidase normal range

0-11

GGT normal range

9-58

5’-Nucleotidase elevations most often due to

hepatic disease

GGT usually elevated in

alcohol abuse/alcoholic liver disease

GGT/ALP ration indicative of alcohol abuse

>2.5

GGT is the most sensitive test for

cholestatic disorders, lacks specificity

total bilirubin normal range

0.3-1.3

indirect bilirubin normal range

0.2-0.9

direct bilirubin normal range

0.1-0.4

icterus visible when

bilirubin > 2-4

indirect hyperbilirubinemia common causes

hemolysis, Gilbert syndrome, Crigler-Najjar syndrome, drugs

hepatitis

histologic patterns of inflammation of heptaocytes

AST and ALT are elevated in

hepatocellular injury

AST normal value

12-38

ALT normal value

7-41

if AST/ALT and cholestatic test are elevated

severe hepatocellular process

extremely high concentrations of AST/AST (>1000) associated with

acute viral hepatitis, severe drug or toxic reactions, ischemic hepatitis

AST elevation without ALT elevation suggest

cardiac or muscle disorder

ammonia normal range

19-60

pancreatitis

inflammation of pancreas

most pancreatitis cases caused by

gallstones and alcohol absue

amylase normal range

20-96

laboratory test for pancreatitis

amylase and lipase

marked hypertriglyceridemia may cause

artificially low amylase

lipase normal range

4-43

lipase can detect acute pancreatitis

3 or mor days after onset

lack of sensitivity for amylase and lipase

can support a diagnosis of pancreatitis but may not be definitive