The comprehensive metabolic panel, all fourteen tests

The comprehensive metabolic panel, or CMP, is fourteen tests run on one tube of blood. MedlinePlus lists them as glucose, calcium, sodium, potassium, bicarbonate, chloride, albumin, total protein, alkaline phosphatase (ALP), ALT, AST, bilirubin, blood urea nitrogen (BUN) and creatinine. Most labs also print an estimated GFR calculated from the creatinine. The basic metabolic panel is the first eight plus BUN and creatinine; the metabolic panel guide covers how the two relate.

The fourteen, by what they check

Kidneys: creatinine, BUN and eGFR

Creatinine is a breakdown product of muscle, cleared almost entirely by the kidneys. eGFR converts it into an estimated filtration rate using age and sex. Since 2021, US labs have been moving to the CKD-EPI 2021 equation published in the New England Journal of Medicine, which removed the race term from earlier versions. Under KDIGO's 2024 guideline, an eGFR below 60 for more than three months indicates chronic kidney disease. The weakness is muscle: more muscle or creatine supplements raise creatinine and lower eGFR; muscle loss does the opposite. KDIGO suggests cystatin C, which does not depend on muscle, when creatinine-based eGFR is likely to be inaccurate. BUN rises with dehydration, high protein intake and bleeding in the gut, as well as with reduced kidney function, which is why it is read with creatinine.

Electrolytes

Sodium tracks water balance more than salt intake; low sodium usually means too much water relative to sodium, from fluids, some medicines or illness. Potassium matters for heart rhythm, and it is the CMP value most prone to a false result: a haemolysed sample, where red cells burst during collection or transport, releases potassium and reads falsely high. A high potassium in an otherwise well person is commonly repeated before anyone acts. Chloride and bicarbonate together describe acid-base balance; a low bicarbonate can follow prolonged vomiting or diarrhoea, which matters on a GLP-1.

Calcium

A large share of blood calcium is bound to albumin, so a low albumin pulls total calcium down without any real change in the active, ionised fraction. Labs or clinicians sometimes "correct" calcium for albumin for that reason. A persistently high calcium is worth following up; it has a short list of causes, mostly involving the parathyroid glands.

Glucose

One value, at one moment. If you fasted at least eight hours it is a fasting glucose, and the ADA thresholds apply: 100 to 125 mg/dL is prediabetes and 126 or more, confirmed, is diabetes. If you ate, it is a random glucose and answers a different question. Glucose in a tube that sits unspun keeps being consumed by blood cells, so a delayed sample can read low. The fasting glucose page has more.

Liver enzymes

ALT is concentrated in the liver; AST is in liver and muscle. In the 2008 weightlifting study in the British Journal of Clinical Pharmacology, an hour of lifting raised both significantly in healthy men for at least seven days, with GGT, ALP and bilirubin staying normal. ALP comes from bile ducts and bone, so it runs higher in teenagers and in bone healing. Bilirubin rises with bile obstruction, with liver disease and, most commonly and harmlessly, with Gilbert syndrome, where bilirubin rises after fasting or illness.

Protein

Albumin is made by the liver and is the main protein in blood. It falls with liver disease, kidney protein loss, poor intake and inflammation, since it is a negative acute-phase protein. Total protein is albumin plus globulins; a high total protein with normal albumin means globulins are up, which is occasionally worth investigating.

Reading it as a set

The CMP is most informative when its lines are read against each other. BUN, creatinine and albumin all a little high together, with sodium at the top of its range, is the shape of a dehydrated draw rather than three separate problems. AST and ALT raised with a normal ALP, GGT and bilirubin after a heavy training week points to muscle; the same enzymes raised with a high ALP or bilirubin points towards the liver and bile ducts. A low albumin with low calcium may be one finding, not two. A high glucose with everything else normal is usually the last meal. None of these patterns is a diagnosis, but they are the questions a clinician will ask first, and noting the context on the day of the draw answers most of them.

Common reasons a CMP looks off

• Dehydration: BUN, creatinine, albumin and sodium all concentrate.
• A hard workout: AST, ALT and creatinine rise.
• A haemolysed sample: potassium and AST rise falsely.
• Eating before the draw: glucose rises.
• Delayed processing: glucose falls.
• Biotin supplements do not usually affect the chemistry tests on a CMP, but they do affect some immunoassays drawn alongside it; see the preparation guide.

Fasting and frequency

MedlinePlus says you may need to fast for several hours before a CMP; the reason is the glucose line. There is no USPSTF recommendation for a routine CMP in adults without symptoms, but it is commonly part of annual bloodwork and part of most baselines before starting a medicine. The what blood tests to get page covers who needs what.

In the app

From a CMP, Peptide AI's metabolic panel reads glucose, ALT, AST, creatinine, eGFR and BUN, and the inflammatory panel reads albumin. Each is plotted against the dose log, so a creatinine bump can be read against a week of vomiting or a new training block. See bloodwork tracking.