The Comprehensive Metabolic Panel (CMP) is a standard group of 14 blood tests that provides healthcare providers with a broad overview of a person’s metabolism and general health status. This panel is frequently ordered for routine screenings or to evaluate the status of the kidneys, liver, electrolytes, and acid-base balance. Although the CMP covers several markers related to waste product clearance, uric acid is not included as one of the standard components in this 14-test profile.
The Specific Uric Acid Test
Uric acid is a natural waste product resulting from the breakdown of purines, chemical compounds found in the body’s cells and in many foods. Most uric acid dissolves in the blood, travels to the kidneys, and is then excreted in urine. Measuring the concentration of this substance requires a specific test, often called a serum urate test, which is separate from the CMP.
A healthcare provider typically orders this test when there is suspicion of a condition related to purine metabolism or excretion. The procedure usually involves drawing a blood sample, but a 24-hour urine collection may also be requested to assess kidney clearance. The primary purpose of this analysis is to help diagnose conditions like gout or to monitor existing conditions that affect uric acid regulation. This test is also utilized to monitor the effects of certain cancer treatments, such as chemotherapy, which can cause a rapid breakdown of cells and a sudden spike in purine release.
Essential Measurements in the CMP
The Comprehensive Metabolic Panel provides a snapshot of several physiological processes through its 14 standard measurements. These tests are grouped into categories, including glucose, electrolytes, proteins, and markers for liver and kidney function. The panel includes four electrolytes—sodium, potassium, chloride, and bicarbonate—which help maintain the body’s fluid balance.
The CMP provides insight into liver function by measuring proteins like albumin and total protein. It also measures specific liver enzymes such as alkaline phosphatase (ALP), alanine transaminase (ALT), and aspartate aminotransferase (AST). The panel also includes tests for blood glucose and total bilirubin, a waste product from red blood cell breakdown.
Confusion often arises because the CMP includes other kidney-related waste products. The CMP specifically measures blood urea nitrogen (BUN) and creatinine, which are markers used to evaluate the kidney’s filtering capacity. BUN is a waste product of protein metabolism, and creatinine is a waste product of muscle metabolism. While these indicate how effectively the kidneys remove metabolic waste, they are chemically distinct from uric acid, a purine metabolite requiring separate analysis.
Clinical Significance of Uric Acid Levels
When a specific uric acid test is performed, the results provide information about the balance between purine production and excretion. Abnormally high levels, known as hyperuricemia, are most commonly associated with gout, a painful form of inflammatory arthritis. Gout occurs when excess uric acid forms needle-like monosodium urate crystals that deposit in the joints, often affecting the big toe.
Sustained hyperuricemia also risks the formation of kidney stones, as excess uric acid can crystallize within the urinary tract. This elevation can result from the kidneys not efficiently excreting the substance or from the body overproducing it. Overproduction is often due to a diet high in purines or certain genetic factors. Hyperuricemia has also been linked to components of the metabolic syndrome, including hypertension and type 2 diabetes.
Conversely, abnormally low levels, or hypouricemia, are less common but can signify underlying health issues. Hypouricemia is defined as a serum urate concentration below 2 mg/dL. This reduction can be due to decreased production, such as from a deficiency in the xanthine oxidase enzyme, or increased excretion by the kidneys.
In some cases, increased excretion is due to hereditary renal hypouricemia, where the kidney’s ability to reabsorb uric acid is impaired. This condition is associated with a risk of exercise-induced acute kidney injury and urolithiasis (stone formation). Low uric acid levels can also be a marker for certain liver or kidney disorders, such as Fanconi syndrome, which affects the kidney tubules.