A hepatic function panel is seven blood tests run from one tube, billed under CPT code 80076, and ordered whenever the question is whether the liver or the bile ducts are involved in something. It is cheap, fast and genuinely useful. It is also read badly more often than almost any other panel, because the seven numbers only mean something as a group — and the test most needed to interpret the group is not on it.
The Verdict
What is on a hepatic function panel
The panel is standardised. ARUP Laboratories lists the components of CPT 80076 as albumin, alkaline phosphatase, AST, ALT, total bilirubin, direct bilirubin and total protein — seven analytes, no more. Because the code is an AMA-recognised panel definition rather than a lab's own product, the composition is the same wherever it is drawn.
| Component | What it reports on | Notes |
|---|---|---|
| ALT (alanine aminotransferase) | Liver cell injury | The most liver-specific number on the panel. Enzyme leaking from damaged liver cells, not a measure of function. |
| AST (aspartate aminotransferase) | Cell injury, not liver-specific | Also abundant in skeletal muscle, heart, kidney and red cells. A hard workout raises it for days. |
| ALP (alkaline phosphatase) | Bile ducts — and bone | The panel's main cholestatic marker. Bone is an equally large source, and nothing on this panel tells you which. |
| Bilirubin, total | Bilirubin handling overall | Rises in both liver-cell disease and bile-duct obstruction, so on its own it does not localise anything. |
| Bilirubin, direct (conjugated) | Which half of the bilirubin is raised | The one analyte here that a CMP does not carry. It is what separates Gilbert's syndrome from obstruction. |
| Albumin | Genuine synthetic function | The liver makes it. Falls in chronic liver disease — but also in inflammation and protein loss, so it is not a clean liver number. |
| Protein, total | Albumin plus everything else | Useful mainly because globulin is calculated from it: total protein minus albumin. |
Two of those rows are doing less work than their names suggest. AST is not a liver-specific enzyme at all — skeletal muscle, heart, kidney and red blood cells all contain it, which is why unaccustomed exercise in the days before a draw is one of the most common reasons a healthy person gets an abnormal panel. And alkaline phosphatase is produced by bone as readily as by bile duct, a problem the next section is entirely about.
Reading the pattern, not the rows
The panel's real output is a pattern rather than seven separate verdicts. The American College of Gastroenterology's 2017 guideline on abnormal liver chemistries defines four, and sorting a result into one of them is what narrows the list of possible causes.
| Pattern | What it looks like | R ratio | What it points at |
|---|---|---|---|
| Hepatocellular | ALT and AST up out of proportion to ALP | R ratio above 5 | Fatty liver disease, alcohol, viral hepatitis, drug injury, autoimmune hepatitis |
| Cholestatic | ALP up out of proportion to ALT and AST | R ratio below 2 | Bile-duct obstruction, gallstones, primary biliary cholangitis, primary sclerosing cholangitis, drug injury — or bone, if the ALP is not hepatic at all |
| Mixed | Both ALP and the transaminases raised | R ratio 2 to 5 | Drug-induced injury is the classic cause of a genuinely mixed picture |
| Isolated hyperbilirubinaemia | Bilirubin raised, everything else normal | R ratio not applicable | Very commonly Gilbert's syndrome when the raised fraction is indirect; haemolysis is the other benign-enzyme cause |
The R ratio
The R ratio turns "disproportionate" into arithmetic. The ACG formula is R = (ALT ÷ ALT ULN) ÷ (ALP ÷ ALP ULN), with above 5 hepatocellular, below 2 cholestatic, and 2 to 5 mixed. It matters because ALT and alkaline phosphatase are measured on scales that are not comparable by eye — an ALT of 80 and an ALP of 180 look similar on paper and are not remotely similar in what they imply. Dividing each by its own upper limit puts them on the same footing before they are compared.
Use the upper limits printed on your own report rather than any figure quoted here. The ACG notes that AST and ALT reference ranges vary between laboratories, and the ratio is only meaningful against the limits the analysing lab actually used.
How big is too big
The size of a transaminase elevation does not identify the cause, but it does determine how much is done about it and how quickly. The ACG bands are worth knowing because they explain why two people with "raised liver enzymes" can be sent down completely different paths.
| Band | ALT and/or AST | What the guideline advises assessing |
|---|---|---|
| Borderline | Under 2× the upper limit of normal | The most common abnormal panel there is. Usually repeated before anything else happens. |
| Mild | 2–5× ULN | ACG advises assessing for hepatitis B and C, alcohol and fatty liver disease, haemochromatosis, Wilson's disease, alpha-1 antitrypsin deficiency, autoimmune hepatitis, and drug or supplement injury. |
| Moderate | 5–15× ULN | The same workup, plus testing for acute hepatitis A, B and C. |
| Severe | Over 15× ULN | Adds assessment for paracetamol (acetaminophen) toxicity and ischaemic hepatitis. |
| Massive | ALT over 10,000 IU/L | A small list of causes: paracetamol overdose, shock liver, and severe acute viral hepatitis. |
Most abnormal panels found on routine screening sit in the borderline band, and most of those are metabolic-dysfunction-associated fatty liver disease, alcohol, medication, or an artefact of the draw. The ACG specifically recommends ultrasound screening for fatty liver in people with a raised BMI and features of metabolic syndrome who have a mildly raised ALT — which describes a large share of everyone who ever sees a mildly abnormal result.
What "normal" means here, and why it is contested
The reference range printed next to your ALT is probably wider than the evidence supports. The ACG summary statement is direct: a true healthy normal ALT in prospectively studied populations without identifiable risk factors for liver disease ranges from 29–33 IU/L for males and 19–25 IU/L for females, and levels above this should be assessed by physicians. Many laboratories still report an upper limit in the 40s or higher, derived from a reference population that included people with undiagnosed fatty liver.
This is the same gap between statistically common and physiologically good that runs through most blood work — the framework in normal vs optimal ranges, and the reason the ALT guide treats the printed range with suspicion. Two further ACG statements sharpen it: an elevated ALT or AST above the upper limit is associated with increased liver-related mortality, and there is a linear relationship between ALT level and body mass index. An ALT of 38 is "normal" on most reports and is not, on the evidence, a reassuring number in a man.
Where the panel is blind
A normal hepatic function panel is weaker evidence than most people take it for. The ACG states that a normal ALT level may not exclude significant liver disease, and the mechanism is straightforward: enzymes leak only while cells are being actively injured. A liver that has already scarred has fewer cells left to leak, so cirrhosis and advanced fibrosis can coexist with seven results in range.
Three specific gaps are worth naming:
- No fibrosis measure. Scarring is the finding that changes prognosis, and nothing here detects it. FIB-4, calculated from AST, ALT, platelets and age, is the usual first-pass screen — which requires a platelet count the panel does not include. Both Labcorp's and Quest's consumer liver products add platelets specifically so they can report it.
- No GGT. Covered above, and the reason a cholestatic pattern often cannot be localised from this panel alone.
- No viral serology, iron studies or autoantibodies. The panel finds an abnormality; the ACG workup that follows — hepatitis B and C testing, transferrin saturation and ferritin, ANA and anti-smooth-muscle antibody, ceruloplasmin in patients under 55 — is all ordered separately.
One practical consequence follows from the fibrosis gap that rarely gets said out loud. If your reason for testing is longevity screening rather than a symptom, a bare hepatic function panel is the wrong instrument: it is built to triage an acute question, and the chronic question — is there scarring accumulating quietly — needs a platelet count at minimum, and imaging to answer properly.
How and when to test
- No fasting is needed for these seven analytes. Fast only if the panel is drawn with a comprehensive metabolic panel or lipids, or if your clinician says otherwise — see whether a hepatic function panel requires fasting.
- Avoid strenuous or unaccustomed exercise for 2–3 days beforehand. This is the most common cause of a spuriously raised AST, and it produces an AST-dominant pattern that can look like liver disease on paper.
- Add GGT if there is any history of a raised alkaline phosphatase.
- Ask for a platelet count if the question is chronic liver risk rather than an acute symptom, so FIB-4 can be calculated.
- Write down every medicine and supplement you take, including over-the-counter painkillers and herbal products. The ACG puts a medication history in its first-line clinical assessment, and supplement-related injury is a routine finding rather than an exotic one.
- Repeat a borderline abnormal result before acting on it. A large share of mildly raised transaminases do not reproduce.
- Keep your previous panels. A trend across three years is more informative than any single set of seven numbers.
When a result warrants seeing a physician
- Any ALT or AST above roughly 5× the upper limit, which moves the workup into a different band.
- A raised bilirubin accompanied by jaundice, dark urine, pale stools or abdominal pain.
- A raised alkaline phosphatase confirmed as hepatic by a raised GGT — the ACG recommends a right-upper-quadrant ultrasound in that setting.
- A falling albumin, particularly alongside any other abnormal result, since it speaks to function rather than injury.
- Any abnormality that persists on a repeat sample without an obvious explanation.
- Any abnormal panel in someone with symptoms of acute hepatitis — the ACG advises immediate specialist referral where there is a prolonged prothrombin time or confusion.
This panel indicates where to look next; it does not conclude anything by itself. Deciding which of the seven numbers matters, whether a pattern is real or an artefact of the draw, and what to order after it, belongs with a clinician who can see the whole result alongside your history, alcohol intake and medications.
Frequently Asked Questions
What is a hepatic function panel?
A hepatic function panel is a group of seven blood tests billed under CPT code 80076: ALT, AST, alkaline phosphatase, total bilirubin, direct bilirubin, albumin and total protein. It is run from a single tube and is the standard first-line blood test when a clinician wants to know whether the liver or the bile ducts are involved in someone's symptoms. Its job is to sort a problem into a pattern — liver-cell injury, bile-duct obstruction, or neither — rather than to name a diagnosis. It is a screening and triage instrument, and it works best when the results are read as a group rather than one row at a time.
What does a hepatic function panel include?
It includes exactly seven measurements. Three are enzymes: ALT and AST, which leak from injured cells, and alkaline phosphatase, which rises when bile flow is obstructed. Two are bilirubin fractions: total bilirubin and direct (conjugated) bilirubin, with the indirect fraction calculated by subtraction. Two are proteins the liver synthesises: albumin and total protein. Notably absent is GGT, which is the test most often needed to interpret a raised alkaline phosphatase, and which has to be ordered separately.
Is a hepatic function panel the same as a liver function test?
They are used interchangeably in everyday speech, but the American College of Gastroenterology argues the term "liver function test" should be retired. Its 2017 guideline states these values are indirect markers of hepatobiliary disease, are not true measures of hepatic function, and are best called liver chemistries or liver tests. The distinction matters clinically. ALT and AST report cell injury, not capacity, so in advanced cirrhosis — when few functioning cells remain to leak anything — both can sit in range while liver function is severely impaired. Only albumin and bilirubin on this panel say anything about what the liver is actually doing.
What does a high ALT on a hepatic function panel mean?
A raised ALT means liver cells are leaking enzyme, and the size of the rise determines how urgently it is chased rather than what caused it. The ACG classifies elevations as borderline under 2× the upper limit of normal, mild at 2–5×, moderate at 5–15×, and severe above 15×. Most raised ALTs found on routine screening are borderline, and the single most common explanation in the general population is metabolic-dysfunction-associated fatty liver disease. Alcohol, prescribed and over-the-counter medicines, herbal supplements, viral hepatitis and recent heavy exercise account for most of the rest. A repeat test is usually the next step, because a single mildly raised value often does not reproduce.
What does a high alkaline phosphatase on this panel mean?
A raised alkaline phosphatase means either the bile ducts or the bones — and the hepatic function panel cannot tell you which. This is the panel's largest blind spot. The ACG guideline recommends confirming that a raised alkaline phosphatase is hepatic in origin by checking GGT, a test not included in the seven. If the GGT is raised alongside it, the source is hepatobiliary and a right-upper-quadrant ultrasound is the recommended next step. If GGT is normal, attention moves to bone, where vitamin D deficiency, Paget's disease, healing fractures and normal growth in adolescents are the usual explanations.
What is the R ratio and how is it calculated?
The R ratio is the arithmetic clinicians use to classify a liver injury pattern objectively rather than by eye. The ACG gives the formula as R equals ALT divided by its upper limit of normal, then divided by alkaline phosphatase divided by its upper limit of normal. An R above 5 defines hepatocellular injury, below 2 defines cholestatic injury, and 2 to 5 is a mixed pattern. The value of the ratio is that it normalises two numbers measured on completely different scales, which is why a panel that "looks liver-ish" by eye sometimes classifies as cholestatic once the calculation is done.
Do I need to fast for a hepatic function panel?
Not for the seven analytes themselves. Both Labcorp and Quest Diagnostics state that their direct-to-consumer liver panels need no special preparation. The complication is that this panel is rarely drawn alone — it is usually collected alongside a comprehensive metabolic panel or a lipid panel, and those do have fasting requirements, which is why patients are so often told to fast anyway. The instruction that governs is the one from the clinician who ordered the draw.
Can a hepatic function panel be normal and the liver still be damaged?
Yes, and this is the single most important limitation to understand. The ACG guideline states plainly that a normal ALT level may not exclude significant liver disease. Cirrhosis, advanced fibrosis and even some cancers can coexist with a completely normal seven-test panel, because enzymes only leak while cells are actively being injured — a scarred, quiet liver leaks nothing. The panel also contains no imaging and no fibrosis measure. Where fibrosis is the actual question, a FIB-4 score or elastography answers it and this panel does not.
How often should a hepatic function panel be repeated?
For an adult with no symptoms, no liver risk factors and a normal previous result, there is no evidence supporting routine repeat testing more often than the annual panel most people already get. Repeat testing is driven by a reason rather than a schedule: an abnormal previous result being followed up, a new medication known to affect the liver, established liver disease being monitored, or a change in alcohol intake. Testing more frequently without a reason mainly produces borderline abnormalities that trigger further tests rather than better outcomes.
Related
- Hepatic function panel vs CMP — which one to order
- What a hepatic function panel costs
- Do you need to fast for a hepatic function panel?
- ALT — the liver marker where normal is higher than healthy
- Alkaline phosphatase — liver or bone?
- GGT — the test that resolves a raised ALP
- Normal vs optimal ranges