Carbon dioxide (CO₂) on a blood test—often reported as Total CO₂ (TCO₂) or bicarbonate (HCO₃⁻)—primarily reflects the level of bicarbonate in your blood, a key buffer that helps maintain stable blood pH. The CO₂ test is usually included on a Comprehensive Metabolic Panel (CMP) or Basic Metabolic Panel (BMP) to evaluate acid–base balance and support interpretation of kidney function, hydration status, and electrolyte patterns. Low CO₂ levels may suggest metabolic acidosis or respiratory alkalosis, while high CO₂ levels may indicate metabolic alkalosis or compensation for chronic respiratory CO₂ retention. Results are most meaningful when interpreted alongside sodium, potassium, chloride, anion gap, creatinine, glucose, and clinical symptoms.

Determine the extent of carbon monoxide poisoning, toxicity; check on the effect of smoking on the patient; work up headache, irritability, nausea, vomiting, vertigo, dyspnea, collapse, coma, convulsions; work up persons exposed to fires and smoke inhalation.

Carbon monoxide levels are of limited value in testing for smoking, since it is cleared rapidly. The half-life of carboxyhemoglobin in individuals with normal cardiopulmonary function is one to two hours. Urinary cotinine, if available, is preferable as a test for tobacco use. Arterial blood gases may be of limited value in treatment decisions for carbon monoxide poisoning.

Carboxyhemoglobin is useful in judging the extent of carbon monoxide toxicity and in considering the effect of smoking on the patient. A direct correlation has been claimed between CO level and symptoms of atherosclerotic diseases, intermittent claudication, angina, and myocardial infarction. Exposure may occur not only from smoking but also from garage exposure, and from various motors.

The novel antibodies salivary gland protein 1 (SP-1), carbonic anhydrase 6 (CA VI) and parotid secretory protein (PSP) have shown to be present in animal models for Sjogren's syndrome (SS) and patients with the disease. The antibodies SP-1, CA VI and PSP occurred earlier in the course of the disease than antibodies to Ro or La.

The novel antibodies salivary gland protein 1 (SP-1), carbonic anhydrase 6 (CA VI) and parotid secretory protein (PSP) have shown to be present in animal models for Sjogren's syndrome (SS) and patients with the disease. The antibodies SP-1, CA VI and PSP occurred earlier in the course of the disease than antibodies to Ro or La.

The novel antibodies salivary gland protein 1 (SP-1), carbonic anhydrase 6 (CA VI) and parotid secretory protein (PSP) have shown to be present in animal models for Sjogren's syndrome (SS) and patients with the disease. The antibodies SP-1, CA VI and PSP occurred earlier in the course of the disease than antibodies to Ro or La.

Carboxycitric is a metabolite of yeast/fungi and general indicator of gastrointestinal dysbiosis. Elevated yeast/fungal metabolites indicate overgrowth in the GI tract.

Carboxycitric is a metabolite of yeast/fungi and general indicator of gastrointestinal dysbiosis. Elevated yeast/fungal metabolites indicate overgrowth in the GI tract.

Carboxycitric acid, an analogue of the Krebs/citric acid cycle, serves as a marker for intestinal microbial overgrowth, particularly involving yeast and fungi. As a byproduct of the Krebs cycle, elevated levels may also point to energy metabolism disorders. Research has shown that children with autism tend to have lower levels of 3-oxoglutaric acid, which is thought to result from increased uptake of these compounds across the blood-brain barrier. Urinary levels of carboxycitric acid have been observed to decrease following nystatin therapy. To identify the root cause, consider testing with a Gut Zoomer, fungal antibodies, or a mycotoxin panel. Implementing multi-strain probiotics and comprehensive gastrointestinal support can help improve this condition.

Carboxyhemoglobin is a form of hemoglobin that develops when carbon monoxide (CO) binds to red blood cells. Carbon monoxide has a much stronger affinity for hemoglobin than oxygen does—over 200 times stronger—so even modest exposure can reduce the body’s ability to carry oxygen. This test measures the percentage of total hemoglobin bound to carbon monoxide and is used to evaluate oxygen-carrying capacity, detect carbon monoxide exposure, and assess smoking status or environmental/occupational risks.

A carboxyhemoglobin level above 2% but below 5% is typically seen in individuals who are exposed to low levels of carbon monoxide, most commonly light or moderate smokers or people who are regularly around secondhand smoke or mild environmental CO sources. While this range is above the normal nonsmoker reference (<2%), it is not generally considered dangerous on its own. However, it does indicate that the body’s oxygen-carrying capacity is slightly reduced, which may contribute to symptoms like mild headaches, fatigue, or decreased exercise tolerance in sensitive individuals. For those who do not smoke, a result in this range may prompt evaluation for hidden carbon monoxide exposure, such as from poor indoor ventilation, gas appliances, garage exhaust, or occupational settings. Reducing environmental CO exposure, improving ventilation, and avoiding smoke can help bring levels back into the nonsmoker range.

Carcinoembryonic Antigen (CEA) is a blood test used primarily to monitor certain cancers — especially colorectal cancer. It is not used to diagnose cancer or screen healthy individuals. Instead, CEA is most useful for tracking treatment response and detecting cancer recurrence over time. Elevated levels can occur in cancer, but also in non-cancer conditions such as liver disease, inflammatory bowel disease, smoking, and chronic lung disease. Because of this, CEA must always be interpreted alongside imaging and clinical history — and trends over time are far more important than a single result.

A low CEA level (within the reference range) generally indicates no active tumor marker elevation.

However:

• Not all cancers produce CEA

• Normal results do not rule out cancer

• Continued monitoring may still be required in high-risk patients

- Anticardiolipins are antibodies produced by the immune system against the platelet membrane phospholipids responsible for the coagulation of blood clots. 

- Anticardiolipin antibodies are often responsible (with lupus anticoagulants and beta-2 glycoprotein antibodies) for the abnormal formation of clots in veins (phlebitis) and arteries (arterial thrombosis). 

- They are involved in antiphospholipid syndrome, which occurs, for example, through repeated miscarriages during the second or third trimester of pregnancy. 

There are three types of anticardiolipin antibodies: IgG, IgA and IgM.

- Anticardiolipins are antibodies produced by the immune system against the platelet membrane phospholipids responsible for the coagulation of blood clots. 

- Anticardiolipin antibodies are often responsible (with lupus anticoagulants and beta-2 glycoprotein antibodies) for the abnormal formation of clots in veins (phlebitis) and arteries (arterial thrombosis). 

- They are involved in antiphospholipid syndrome, which occurs, for example, through repeated miscarriages during the second or third trimester of pregnancy. 

There are three types of anticardiolipin antibodies: IgG, IgA and IgM.

The Cardiolipin Ab IgM test measures IgM-class antibodies directed against cardiolipin, a phospholipid found in cell membranes. Elevated levels are associated with antiphospholipid syndrome (APS), which can cause blood clots and recurrent miscarriage. Normal range: 0–12 MPL. Results above 40 MPL are considered high positive and meet APS diagnostic criteria when confirmed on repeat testing 12 weeks apart.

L-carnitine is an amino acid derivitive of the essential amino acids L-lysine and methonine. The conversion to carnitine requires niacin (B3), vitamins B6 and C, and iron. It is found in nearly all cells of the body but chiefly in the liver and kidney. Carnitine is essential for the transportation of long-chain fatty acids across the inner mitochondrial membranes in the mitochondria, where they are metabolized by beta-oxidation to produce biological energy in the form of adenosine triphosphate (ATP). L-Carnitine also is required to remove short- and medium-chain fatty acids from the mitochondria. This removal optimizes energy production by maintaining coenzyme A at optimal levels for normal metabolism and energy production.

Carnitine esters are special molecules in our bodies that help turn fat into energy. Think of them as tiny taxis that pick up fat from our bloodstream and take it into the mitochondria, the powerhouses of our cells. Inside the mitochondria, this fat is burned for fuel, giving us the energy we need to function. These esters are made when carnitine, a substance our bodies produce and also get from food, links up with fatty acids.

This process is super important, especially in parts of our body like the heart and muscles, which use a lot of energy and therefore burn a lot of fat. If our body doesn't handle these carnitine esters correctly, it can mess up how we use fat for energy. This can lead to different health issues, such as muscle weakness or problems with our metabolism (the chemical reactions that keep us alive and kicking).

Doctors can check the levels of these esters in our blood to see if everything is working right with our body's energy production. Sometimes, when there's a problem with this system, doctors recommend taking extra carnitine as a supplement. But, the benefits of taking these supplements are still being studied, and it's not yet clear how much they help with various health conditions.