Is Total Serum Bilirubin Included in a CMP?
No, total serum bilirubin is NOT included in a standard comprehensive metabolic panel (CMP).
What's Actually in Each Panel
A CMP typically includes 14 tests:
- Glucose
- Calcium
- Sodium, potassium, chloride, bicarbonate (electrolytes)
- BUN and creatinine (kidney function)
- Albumin and total protein
- ALP (alkaline phosphatase)
- ALT and AST (liver enzymes)
A basic metabolic panel (BMP) includes only 8 tests (glucose, calcium, and the electrolytes/kidney markers), excluding the liver-related tests entirely 1.
Why This Matters Clinically
Total bilirubin must be ordered separately as part of a liver function test panel or as an individual test 2. While the CMP includes some liver-related markers (ALT, AST, ALP, albumin), it does not include bilirubin measurements 1.
Key Clinical Implications:
If you suspect cholestasis or jaundice, you need to specifically order total bilirubin (and potentially fractionated bilirubin) in addition to the CMP 3
Most laboratories routinely report total bilirubin when liver function tests are ordered, which comprises both unconjugated and conjugated fractions 2
The CMP's albumin level can provide some information about liver synthetic function, but this is not a substitute for bilirubin when evaluating jaundice or cholestasis 2
Common Clinical Pitfall
Don't assume ordering a CMP will give you bilirubin levels. If you're evaluating for:
- Jaundice
- Suspected Gilbert's syndrome
- Cholestasis
- Hemolysis
- Neonatal hyperbilirubinemia
You must specifically order bilirubin testing separately from the CMP 3, 1.