High Bilirubin Blood Test: Causes, Normal Range, Jaundice, Liver Disease & Laboratory Interpretation (2026)
Last Updated: August 20, 2026
A bilirubin blood test measures bilirubin in serum or plasma and is an important component of the laboratory evaluation of jaundice, liver disease, bile duct obstruction, hemolysis, and disorders of bilirubin metabolism.
Bilirubin is a yellow pigment produced mainly during the normal breakdown of hemoglobin from aging red blood cells. After formation, bilirubin is transported to the liver, conjugated, excreted into bile, and ultimately eliminated through the gastrointestinal tract.
When bilirubin production increases, hepatic uptake or conjugation is impaired, or bile excretion is obstructed, bilirubin may accumulate in the bloodstream. This condition is called hyperbilirubinemia.
Laboratory interpretation requires more than simply determining whether total bilirubin is high. The distinction between total, direct (conjugated), and indirect (unconjugated) bilirubin can provide important clues about the underlying mechanism.
Quick Laboratory Summary
- Bilirubin is produced mainly from heme breakdown.
- Total bilirubin includes conjugated and unconjugated fractions.
- Indirect bilirubin is generally calculated from total minus direct bilirubin.
- Predominantly indirect hyperbilirubinemia may occur with hemolysis or impaired conjugation.
- Predominantly direct hyperbilirubinemia may occur with hepatocellular disease or cholestasis.
- Conjugated bilirubin is water soluble and may appear in urine.
- Unconjugated bilirubin is albumin-bound and is not normally excreted in urine.
- Specimens should be protected from excessive light exposure because bilirubin is photosensitive.
1. What Is Bilirubin?
Bilirubin is a yellow-orange pigment generated primarily from the breakdown of heme. Most bilirubin originates from hemoglobin released when aging red blood cells are removed from circulation.
Smaller amounts may arise from ineffective erythropoiesis and the turnover of other heme-containing proteins.
Because unconjugated bilirubin is poorly soluble in water, it circulates bound mainly to albumin until it reaches the liver.
2. Bilirubin Metabolism
Understanding bilirubin metabolism is essential for interpreting abnormal results.
Step 1: Red Blood Cell Breakdown
Senescent red blood cells are removed mainly by macrophages in the reticuloendothelial system.
Step 2: Heme Conversion
Heme is converted to biliverdin and subsequently to bilirubin.
Step 3: Transport to the Liver
Unconjugated bilirubin circulates bound to albumin because it is poorly water soluble.
Step 4: Hepatic Uptake and Conjugation
Hepatocytes take up bilirubin and conjugate it primarily with glucuronic acid through the enzyme UDP-glucuronosyltransferase.
Conjugation makes bilirubin substantially more water soluble.
Step 5: Biliary Excretion
Conjugated bilirubin is secreted into bile and transported through the biliary system into the intestine.
Step 6: Intestinal Metabolism
Intestinal bacteria metabolize bilirubin into compounds including urobilinogen. Further metabolism contributes to the normal brown color of stool.
3. What Is a Bilirubin Blood Test?
A bilirubin blood test measures bilirubin concentration in serum or plasma.
Depending on the laboratory, the report may include:
- Total bilirubin
- Direct bilirubin
- Calculated indirect bilirubin
The test may be requested when evaluating:
- Jaundice
- Abnormal liver tests
- Hepatitis
- Hemolysis
- Gallstones
- Bile duct obstruction
- Cholestasis
- Newborn jaundice
- Drug-induced liver injury
- Inherited disorders of bilirubin metabolism
4. Bilirubin Normal Range
Reference intervals vary according to laboratory, analytical method, age, and patient population.
| Test Illustrative Adult Reference Value | |
|---|---|
| Total Bilirubin | Approximately 0.1–1.2 mg/dL |
| Direct Bilirubin | Usually <0.3 mg/dL |
| Indirect Bilirubin | Calculated from total minus direct bilirubin |
Important: These values are educational examples. Always use the reference interval reported by the testing laboratory. Neonatal bilirubin requires age-specific interpretation and should not be interpreted using adult reference ranges.
Bilirubin Unit Conversion
Bilirubin may be reported in mg/dL or µmol/L.
1 mg/dL bilirubin ≈ 17.1 µmol/L
For example:
2.0 mg/dL ≈ 34.2 µmol/L.
5. Total Bilirubin
Total bilirubin represents the bilirubin measured across the major circulating fractions.
An elevated total bilirubin should generally be interpreted with the direct fraction when determining whether the abnormality is predominantly conjugated or unconjugated.
Total bilirubin alone cannot reliably identify the cause of hyperbilirubinemia.
6. Direct Bilirubin
Direct bilirubin broadly reflects the conjugated bilirubin fraction measured by routine laboratory methods, although the analytical term “direct” is not perfectly identical to a pure measurement of conjugated bilirubin in every method.
An increased direct fraction may occur with:
- Hepatocellular injury
- Intrahepatic cholestasis
- Extrahepatic biliary obstruction
- Gallstones obstructing bile flow
- Drug-induced cholestasis
- Selected inherited disorders
7. Indirect Bilirubin
Indirect bilirubin is commonly estimated mathematically:
Indirect Bilirubin = Total Bilirubin − Direct Bilirubin
Predominantly indirect hyperbilirubinemia may occur because of:
- Hemolysis
- Ineffective erythropoiesis
- Resorption of large hematomas
- Gilbert syndrome
- Crigler-Najjar syndrome
- Reduced hepatic uptake
- Impaired bilirubin conjugation
8. What Does High Bilirubin Mean?
An elevated bilirubin concentration is called hyperbilirubinemia.
The major mechanisms include:
- Increased bilirubin production
- Reduced hepatic uptake
- Impaired conjugation
- Hepatocellular dysfunction
- Reduced biliary excretion
- Bile duct obstruction
The pattern of direct and indirect bilirubin helps narrow the differential diagnosis.
9. Causes of High Bilirubin
| Mechanism Possible Causes Typical Pattern | ||
|---|---|---|
| Increased production | Hemolysis, ineffective erythropoiesis | Predominantly indirect |
| Impaired conjugation | Gilbert syndrome, Crigler-Najjar syndrome | Predominantly indirect |
| Hepatocellular injury | Viral hepatitis, toxic injury, alcohol-related disease | Mixed or direct-predominant |
| Cholestasis | Drug-induced cholestasis, biliary disease | Predominantly direct |
| Extrahepatic obstruction | Gallstone, biliary stricture, pancreatic or biliary tumor | Predominantly direct |
10. Unconjugated Hyperbilirubinemia
Predominantly unconjugated hyperbilirubinemia generally suggests excessive bilirubin production, impaired hepatic uptake, or reduced conjugation.
Common Laboratory Considerations
- Hemoglobin
- Reticulocyte count
- LDH
- Haptoglobin
- Peripheral blood smear
- ALT and AST
- Clinical history
When bilirubin is elevated but liver enzymes are otherwise relatively normal, fractionation can be especially useful.
11. Conjugated Hyperbilirubinemia
Predominantly conjugated hyperbilirubinemia suggests impaired excretion of conjugated bilirubin.
Major categories include:
- Hepatocellular dysfunction
- Intrahepatic cholestasis
- Extrahepatic obstruction
Laboratory interpretation should include ALT, AST, ALP and, where appropriate, GGT together with clinical findings and imaging.
12. Bilirubin and Jaundice
Jaundice is yellow discoloration of the skin, sclerae, and mucous membranes caused by accumulation of bilirubin.
Visible jaundice often becomes apparent when serum bilirubin rises to approximately 2–3 mg/dL, although visibility varies with lighting, skin tone, and clinical circumstances.
Possible Associated Symptoms
- Yellow eyes or skin
- Dark urine
- Pale or clay-colored stool
- Pruritus
- Abdominal pain
- Nausea
- Fatigue
Clinical Alert: New jaundice, particularly when associated with fever, severe abdominal pain, confusion, bleeding, persistent vomiting, or significant illness, requires prompt clinical evaluation.
13. Hemolysis and Bilirubin
Accelerated destruction of red blood cells increases heme breakdown and bilirubin production.
A hemolytic pattern may include:
- Increased indirect bilirubin
- Increased LDH
- Reduced haptoglobin
- Reticulocytosis
- Anemia
- Characteristic peripheral smear findings depending on cause
Important distinction: In-vivo hemolysis is a clinical process. In-vitro hemolysis caused by poor specimen collection is an analytical/preanalytical problem. They must not be confused.
14. Gilbert Syndrome
Gilbert syndrome is a common inherited condition associated with reduced bilirubin conjugation.
The typical laboratory pattern is:
- Mild elevation of total bilirubin
- Predominantly unconjugated bilirubin
- Otherwise normal liver chemistry in uncomplicated cases
- No evidence of hemolysis
Bilirubin may fluctuate and can increase during fasting, illness, stress, or dehydration.
Gilbert syndrome is generally benign, but alternative causes of hyperbilirubinemia should be excluded when clinically appropriate.
15. Liver Disease and High Bilirubin
Hepatocellular disease can interfere with bilirubin uptake, conjugation, and excretion.
Possible causes include:
- Viral hepatitis
- Alcohol-related liver disease
- Drug-induced liver injury
- Autoimmune hepatitis
- Advanced chronic liver disease
- Acute liver failure
- Metabolic liver disorders
Bilirubin should therefore be interpreted alongside other laboratory markers rather than being considered a stand-alone “liver function” measurement.
16. Cholestasis and Bile Duct Obstruction
Cholestasis occurs when normal bile formation or bile flow is impaired.
A cholestatic laboratory pattern commonly includes:
- Increased alkaline phosphatase
- Often increased GGT
- Increased direct bilirubin when obstruction is significant
- Variable ALT and AST elevation
Possible causes include:
- Gallstones
- Biliary strictures
- Pancreatic disease
- Biliary tumors
- Drug-induced cholestasis
- Primary biliary cholangitis
- Primary sclerosing cholangitis
17. Gallstones and Bilirubin
Gallstones can cause hyperbilirubinemia when they obstruct bile flow, particularly when a stone enters the common bile duct.
Possible laboratory findings include:
- Increased direct bilirubin
- Increased ALP
- Increased GGT
- Variable ALT and AST elevation
Laboratory testing cannot by itself confirm the location of biliary obstruction; imaging is generally required.
18. Bilirubin in Newborns
Neonatal bilirubin interpretation is fundamentally different from routine adult interpretation.
Many newborns develop transient unconjugated hyperbilirubinemia because bilirubin production is relatively high and hepatic conjugation and elimination pathways are still maturing.
However, severe unconjugated hyperbilirubinemia can be dangerous because bilirubin may cross the blood-brain barrier and cause bilirubin-induced neurologic dysfunction.
Important: Neonatal bilirubin must be interpreted according to the infant's age in hours, gestational age, risk factors, bilirubin trajectory, and current pediatric treatment guidelines. Adult reference intervals must never be used to determine neonatal treatment.
19. Bilirubin in Urine
Normally, significant bilirubin should not be detected in urine.
Conjugated bilirubin is water soluble and can be excreted by the kidneys when its blood concentration rises.
Therefore, bilirubinuria may occur with:
- Hepatocellular disease
- Cholestasis
- Biliary obstruction
Unconjugated bilirubin is albumin-bound and is not normally filtered into urine.
Laboratory Pearl: Elevated serum bilirubin with bilirubinuria supports the presence of a conjugated component. Predominantly unconjugated hyperbilirubinemia does not normally produce bilirubinuria.
20. Bilirubin With ALT, AST, ALP and GGT
Bilirubin becomes much more informative when interpreted alongside the rest of the liver chemistry profile.
| Pattern Laboratory Findings Possible Interpretation | ||
|---|---|---|
| Hepatocellular | ALT/AST disproportionately elevated | Hepatocellular injury |
| Cholestatic | ALP disproportionately elevated, often with GGT | Impaired bile flow |
| Indirect bilirubin predominance | Indirect bilirubin elevated with otherwise limited liver chemistry abnormalities | Hemolysis or impaired conjugation |
| Mixed | ALT/AST and ALP abnormalities with hyperbilirubinemia | Overlapping hepatocellular and cholestatic processes |
21. Specimen Requirements
Serum or plasma may be used depending on the analytical platform and manufacturer instructions.
Laboratory procedures should define:
- Accepted specimen type
- Collection tube
- Minimum sample volume
- Centrifugation requirements
- Storage conditions
- Stability
- Light-protection requirements
- Interference limits
- Specimen rejection criteria
22. Is Fasting Required for a Bilirubin Test?
Fasting is not universally required for every bilirubin test. Requirements depend on the laboratory, the clinical indication, and whether bilirubin is being measured with other tests.
Some laboratories or clinicians may request fasting or specific preparation.
Patients should follow the instructions provided by the ordering clinician or testing laboratory.
23. Light Exposure and Bilirubin
Bilirubin is photosensitive.
Exposure of a specimen to light can degrade bilirubin and may cause a falsely decreased result.
Laboratories should follow validated procedures for specimen handling, particularly when transportation or testing is delayed.
Preanalytical Pearl: Inadequate protection from light can result in bilirubin degradation and potentially underestimate the patient's true concentration.
24. Preanalytical Factors Affecting Bilirubin
Light Exposure
Excessive light exposure may reduce measured bilirubin.
Hemolysis
Hemolysis may interfere with bilirubin assays depending on the analytical method and degree of hemolysis.
Lipemia
Marked lipemia can cause spectrophotometric interference in some methods.
Medication Effects
Some medications may influence bilirubin concentrations physiologically or interfere analytically.
Fasting
Fasting can increase unconjugated bilirubin in susceptible individuals, particularly patients with Gilbert syndrome.
Specimen Storage
Storage time, temperature, and exposure to light should comply with analyzer-specific and laboratory-validated procedures.
25. Laboratory Methods for Bilirubin
Bilirubin can be measured using several analytical approaches.
Common laboratory approaches include:
- Diazo-based methods
- Modified diazo methods
- Direct spectrophotometric methods in selected applications
- Dry chemistry methods
Method characteristics differ between analyzer platforms, so reference intervals and interference limits must be method appropriate.
26. Diazo Method
Many routine bilirubin assays are based on the diazo reaction.
Bilirubin reacts with a diazonium compound to form a colored azobilirubin product that can be quantified photometrically.
Direct bilirubin reacts under specified assay conditions without the accelerator required for measuring additional bilirubin fractions in many traditional methods.
Total bilirubin methods facilitate reaction of a broader bilirubin fraction using assay-specific reagents.
Analytical Note: “Direct bilirubin” is an operational laboratory measurement and should not always be assumed to represent exclusively one chemically pure bilirubin species.
27. Analytical Interferences
Interference varies according to analyzer and reagent system.
Potential concerns include:
- Hemolysis
- Lipemia
- Very high bilirubin concentrations
- Drug-related interference
- Paraproteins
- Reagent deterioration
- Calibration error
- Incorrect sample handling
Laboratory Principle: Never apply generic hemolysis, icterus, or lipemia thresholds to every bilirubin method. Use manufacturer-specific interference limits and locally verified procedures.
28. Quality Control for Bilirubin Testing
Internal quality control must be acceptable before patient bilirubin results are released.
QC monitoring should include:
- Appropriate control levels
- Levey-Jennings charts
- Laboratory-defined QC rules
- Calibration status
- Reagent lot changes
- Control lot changes
- Instrument maintenance
- Shifts and trends
- External quality assessment or proficiency testing
What to Do if Bilirubin QC Is Out of Range
- Do not release potentially affected patient results.
- Verify control identification, lot, expiration, preparation, and storage.
- Review reagent lot, expiration, and onboard stability.
- Check analyzer alarms and maintenance status.
- Review calibration status.
- Determine whether the failure suggests random or systematic error.
- Inspect control and reagent handling.
- Repeat QC only when justified by the investigation.
- Use fresh control material if deterioration is suspected.
- Recalibrate when appropriate.
- Resume reporting only after acceptable QC performance is restored.
- Assess whether previously analyzed patient specimens require repeat testing.
- Document corrective action according to laboratory policy.
29. Delta Check and Result Validation
A bilirubin delta check compares a patient's current result with previous measurements.
An unexpected change may reflect:
- True progression or improvement of disease
- New biliary obstruction
- Hemolysis
- Specimen identification error
- Preanalytical error
- Analytical interference
- Changes in treatment
Delta-check thresholds should be defined by individual laboratory policy and patient population.
30. Practical Laboratory Interpretation Algorithm
- Verify patient identification and specimen labeling.
- Check specimen integrity and light-protection requirements.
- Confirm acceptable QC performance.
- Review total bilirubin.
- Review direct bilirubin when available.
- Calculate or review indirect bilirubin.
- Determine whether the pattern is predominantly unconjugated, conjugated, or mixed.
- Review ALT and AST.
- Review ALP and GGT when available.
- If indirect bilirubin predominates, consider hemolysis and impaired conjugation.
- Review hemoglobin, reticulocytes, LDH, haptoglobin, and smear when hemolysis is suspected.
- If direct bilirubin predominates, evaluate hepatocellular disease and cholestasis.
- Review urine bilirubin when clinically relevant.
- Compare with previous bilirubin results.
- Review medications and clinical history.
- Correlate with imaging when biliary obstruction is suspected.
- Interpret neonatal bilirubin using neonatal-specific guidance.
31. Clinical and Laboratory Case Studies
Case 1: Mild Isolated Indirect Hyperbilirubinemia
A young adult has:
- Total bilirubin: 2.1 mg/dL
- Direct bilirubin: 0.3 mg/dL
- ALT: normal
- AST: normal
- ALP: normal
- Hemoglobin: normal
Interpretation: The pattern is predominantly unconjugated. Gilbert syndrome is one possible explanation after clinically important alternative causes, particularly hemolysis and liver disease, have been considered.
Case 2: Indirect Bilirubin With Hemolysis
Results:
- Indirect bilirubin: increased
- LDH: increased
- Haptoglobin: decreased
- Reticulocytes: increased
- Hemoglobin: decreased
Interpretation: This combination supports increased red-cell destruction and should prompt evaluation for the cause of hemolysis.
Case 3: Direct Hyperbilirubinemia With Cholestatic Pattern
Results:
- Total bilirubin: increased
- Direct bilirubin: increased
- ALP: markedly increased
- GGT: increased
- ALT/AST: moderately increased
Interpretation: The pattern suggests cholestasis. Clinical assessment and imaging may be needed to distinguish intrahepatic from extrahepatic causes.
Case 4: Acute Hepatocellular Injury
Results:
- ALT: markedly increased
- AST: markedly increased
- Total bilirubin: increased
- Direct bilirubin: increased
Interpretation: This pattern may occur with significant hepatocellular injury. Viral, drug-related, ischemic, autoimmune, and other causes should be evaluated clinically.
Case 5: Gallstone Obstruction
A patient presents with jaundice and right upper abdominal pain.
Results show:
- Direct bilirubin: increased
- ALP: increased
- GGT: increased
Interpretation: Biliary obstruction is an important consideration. Imaging is needed to determine whether a stone or another obstructive process is present.
Case 6: Bilirubinuria
Urinalysis shows bilirubin positivity together with increased serum direct bilirubin.
Interpretation: The findings are compatible with conjugated hyperbilirubinemia and support evaluation for hepatobiliary disease or impaired bile excretion.
Case 7: Unexpectedly Low Repeat Bilirubin
A previously elevated bilirubin result is followed by an unexpectedly low value from a specimen that experienced prolonged light exposure.
Interpretation: Preanalytical bilirubin degradation should be considered. Specimen handling should be reviewed and repeat collection may be appropriate.
32. Bilirubin and CBC
CBC results may provide important information when indirect hyperbilirubinemia is suspected to result from hemolysis.
Relevant findings include:
- Hemoglobin concentration
- Hematocrit
- MCV
- RDW
- Reticulocyte response
- Peripheral smear findings
Bilirubin should therefore be correlated with hematology results when red-cell destruction is part of the differential diagnosis.
33. Bilirubin and Ferritin
Ferritin and bilirubin represent different physiological processes, but both can be abnormal in liver disease, inflammation, hemolysis, and systemic illness.
34. Bilirubin and Iron Studies
Iron studies may be useful when anemia, ineffective erythropoiesis, chronic disease, or iron overload is being investigated alongside bilirubin abnormalities.
35. Bilirubin and Vitamin B12
Severe ineffective erythropoiesis associated with vitamin B12 deficiency may increase intracellular red-cell precursor destruction and can contribute to indirect bilirubin elevation in selected patients.
36. Bilirubin and CRP
CRP is an inflammatory marker and should not be interpreted as a bilirubin or liver-specific test.
Nevertheless, CRP may provide complementary information when infection or systemic inflammation is part of the clinical presentation.
37. Bilirubin and Procalcitonin
In critically ill patients with jaundice and suspected bacterial infection or sepsis, procalcitonin may sometimes be measured as part of the broader clinical assessment.
It does not identify the cause of hyperbilirubinemia and should be interpreted according to its own clinical context.
38. Frequently Asked Questions
What is a bilirubin blood test?
A bilirubin blood test measures bilirubin in the blood and is commonly used when evaluating jaundice, liver disease, bile duct obstruction, hemolysis, and disorders of bilirubin metabolism.
What is a normal total bilirubin level?
A commonly cited adult reference interval is approximately 0.1–1.2 mg/dL, but the correct reference interval is the one provided by the testing laboratory.
What causes high bilirubin?
High bilirubin may result from increased red-cell breakdown, impaired hepatic uptake or conjugation, hepatocellular disease, cholestasis, or bile duct obstruction.
What is the difference between direct and indirect bilirubin?
Direct bilirubin broadly represents conjugated, more water-soluble bilirubin, while indirect bilirubin mainly represents unconjugated bilirubin and is commonly calculated by subtracting direct bilirubin from total bilirubin.
Does high bilirubin always mean liver disease?
No. High bilirubin may also occur with hemolysis, Gilbert syndrome, ineffective erythropoiesis, inherited bilirubin disorders, and other conditions.
Can high bilirubin cause yellow eyes?
Yes. Hyperbilirubinemia can cause scleral icterus and jaundice. Visible jaundice often becomes apparent when bilirubin rises to approximately 2–3 mg/dL, although this varies.
Can Gilbert syndrome cause high bilirubin?
Yes. Gilbert syndrome typically causes mild, intermittent, predominantly unconjugated hyperbilirubinemia without significant liver injury.
Can hemolysis cause high bilirubin?
Yes. Increased destruction of red blood cells increases bilirubin production and commonly causes predominantly unconjugated hyperbilirubinemia.
Why is bilirubin found in urine?
Conjugated bilirubin is water soluble and may appear in urine when its blood concentration increases. Unconjugated bilirubin is albumin-bound and is not normally excreted in urine.
Does a bilirubin specimen need protection from light?
Yes. Bilirubin is photosensitive, and excessive light exposure may reduce the measured concentration. Laboratories should follow validated specimen-handling procedures.
Is fasting required for a bilirubin test?
Not universally. Preparation requirements vary according to the laboratory, clinical indication, and other tests being performed.
What tests are commonly interpreted with bilirubin?
Bilirubin is commonly interpreted with ALT, AST, alkaline phosphatase, GGT, CBC, reticulocyte count, LDH, haptoglobin, urinalysis, and other tests selected according to the suspected cause.
39. Authoritative References
- MedlinePlus — Bilirubin Blood Test
- MedlinePlus Medical Encyclopedia — Bilirubin Blood Test
- MedlinePlus — Bilirubin in Urine
- Merck Manual Professional — Laboratory Tests of the Liver and Gallbladder
- Merck Manual Professional — Jaundice
Evidence Note: Bilirubin reference intervals, neonatal treatment thresholds, liver-test interpretation, and diagnostic criteria vary according to patient age, analytical method, clinical context, and current clinical guidelines. Laboratory-specific reference intervals and current professional guidance should always take precedence over general educational ranges.
40. Conclusion
The bilirubin blood test is an important laboratory investigation for evaluating jaundice, liver disease, bile duct obstruction, hemolysis, and inherited disorders of bilirubin metabolism.
The most useful interpretation begins by determining whether hyperbilirubinemia is predominantly unconjugated, conjugated, or mixed.
Predominantly unconjugated bilirubin may suggest increased bilirubin production or impaired conjugation, whereas predominantly conjugated hyperbilirubinemia may suggest hepatocellular dysfunction or impaired bile flow.
Bilirubin should not be interpreted in isolation. ALT, AST, ALP, GGT, CBC, reticulocyte count, LDH, haptoglobin, urinalysis, medication history, symptoms, previous results, and imaging may all contribute to determining the cause.
From a laboratory perspective, correct specimen handling is particularly important because bilirubin is photosensitive. Analytical method, interference, calibration, internal quality control, and delta checks must also be considered before patient results are released.
Medical Disclaimer: This article is intended for educational and laboratory-training purposes only. It does not replace individualized medical assessment, diagnosis, treatment, current clinical guidelines, local laboratory procedures, manufacturer instructions, institutional policies, or specialist consultation. Reference intervals and clinical decision limits may vary by laboratory, analytical method, age, and patient population.
Prepared for: MedLab Academy Category: Clinical Chemistry / Liver Function Tests Last Updated: August 20, 2026