A full blood panel typically includes three core tests: a complete blood count (CBC), a comprehensive metabolic panel (CMP), and a lipid panel. Together, these cover around 30 individual measurements that assess your blood cells, organ function, electrolyte balance, blood sugar, and cholesterol. Depending on your doctor’s order, a thyroid screening or hemoglobin A1c test may also be added.
Complete Blood Count (CBC)
The CBC is the most frequently ordered blood test and gives a snapshot of the cells circulating in your bloodstream. It measures three main cell types: red blood cells, white blood cells, and platelets.
For red blood cells, the CBC reports your red cell count, hemoglobin (the oxygen-carrying protein inside those cells), and hematocrit (the percentage of your blood volume made up of red cells). It also calculates a set of red cell indices that describe the size and hemoglobin content of your average red blood cell. These indices help distinguish between different types of anemia. For example, iron deficiency tends to produce smaller-than-normal red cells, while a vitamin B12 deficiency produces larger ones. A measurement called red cell distribution width shows how much variation there is in cell size, which can be an early clue that something is off even when other numbers look normal.
The white blood cell portion reports your total white cell count plus a breakdown called the differential. The differential counts five specific types: neutrophils (your main defense against bacteria and viruses), lymphocytes (which include T cells and B cells critical for immune memory), monocytes (which clear out dead cells and fight infections), eosinophils (involved in allergic responses and parasite defense), and basophils (which also play a role in allergic reactions). Each type is reported both as a percentage of total white cells and as an absolute count. A spike in one type with normal levels of the others can point toward a specific cause, like a bacterial infection raising neutrophils or allergies raising eosinophils.
Platelet count rounds out the CBC. Platelets are the cell fragments responsible for clotting. Too few can mean excessive bleeding risk; too many can increase the chance of abnormal clots.
Comprehensive Metabolic Panel (CMP)
The CMP measures 14 substances in your blood and is the main window into how your kidneys, liver, and metabolism are performing.
Blood Sugar and Electrolytes
Glucose is the panel’s blood sugar measurement, with a normal fasting range of 70 to 99 mg/dL. Results above that range can signal prediabetes or diabetes. The CMP also measures four key electrolytes: sodium (136 to 145 mEq/L), potassium (3.5 to 5.0 mEq/L), chloride (98 to 106 mmol/L), and carbon dioxide/bicarbonate (23 to 30 mmol/L). These control fluid balance, nerve signaling, muscle contraction, and your blood’s acid-base balance. Even small shifts in potassium, for instance, can affect heart rhythm.
Calcium is also included, with a normal range of 8.6 to 10.2 mg/dL. It’s essential for bone health, but abnormal blood calcium levels more commonly point to parathyroid or kidney issues than to dietary calcium intake.
Kidney Markers
Two measurements assess kidney health: blood urea nitrogen (BUN) and creatinine. Both are waste products your kidneys filter out of the blood. BUN normally falls between 8 and 20 mg/dL, and creatinine runs 0.5 to 1.1 mg/dL for women and 0.7 to 1.3 mg/dL for men. Creatinine is the more reliable indicator of kidney function because BUN can fluctuate with diet and hydration. Many labs also calculate an estimated glomerular filtration rate (eGFR) from your creatinine result, which gives a more practical picture of how well your kidneys are filtering.
Liver Markers
The CMP includes three liver enzymes and one waste product. ALT and AST (both normally 10 to 40 IU/L) are released when liver cells are injured, so elevated levels can indicate inflammation from alcohol use, fatty liver disease, viral hepatitis, or medication side effects. Alkaline phosphatase (ALP), normal at 30 to 120 IU/L, rises with bile duct problems or certain bone conditions. Total bilirubin (0.3 to 1.0 mg/dL) is a yellow pigment processed by the liver. High bilirubin can cause jaundice and may signal liver disease or a problem with red blood cell breakdown.
Proteins
Total protein and albumin are the final two CMP measurements. Albumin, made by the liver, normally runs 3.5 to 5.5 g/dL and helps maintain fluid balance in your blood vessels. Low albumin can reflect liver disease, kidney disease, or chronic malnutrition. Total protein (5.5 to 9.0 g/dL) combines albumin with globulins, a group of proteins that includes immune system antibodies. Some labs calculate an albumin-to-globulin ratio. A low ratio can suggest autoimmune conditions, liver cirrhosis, or kidney disease, while a high ratio is less common and may point to certain genetic disorders or blood cancers.
Lipid Panel
The lipid panel measures four values related to cholesterol and fat in your blood. Total cholesterol is the broadest number. LDL cholesterol is the “bad” type that builds up as plaque inside artery walls. HDL cholesterol is the “good” type that helps remove LDL from the bloodstream. Triglycerides are a type of fat your body stores for energy; high levels raise cardiovascular risk independently of cholesterol.
Some reports also include VLDL cholesterol, which carries triglycerides through the blood and contributes to plaque buildup. VLDL is difficult to measure directly, so labs typically estimate it from your triglyceride level.
Tests Often Added to a Full Panel
Beyond the CBC, CMP, and lipid panel, doctors frequently tack on a few extra tests depending on your age, symptoms, and risk factors.
A thyroid-stimulating hormone (TSH) test is the most common thyroid screen. TSH is produced by the pituitary gland and tells your thyroid how much hormone to make. An abnormal TSH usually prompts a follow-up test for free T4 (thyroxine), which measures the actual hormone your thyroid releases. Together, these two tests can identify an underactive or overactive thyroid. A full thyroid panel goes further with T3, thyroid antibodies, and other markers, but that’s typically reserved for people with known or suspected thyroid conditions.
Hemoglobin A1c (HbA1c) reflects your average blood sugar over the past two to three months. It’s a key screening test for diabetes and prediabetes recommended by the American Diabetes Association and the U.S. Preventive Services Task Force. While fasting glucose on the CMP gives a single-moment reading, HbA1c captures the bigger trend.
Fasting and Preparation
You’ll typically need to fast for 8 to 12 hours before your blood draw, meaning no food or drinks other than plain water. The lipid panel and glucose test are the main reasons for fasting, since eating can temporarily spike triglycerides and blood sugar and skew results. Some providers also request fasting for liver and kidney function tests, though this varies by lab.
If you’re unsure whether to fast, check with your provider’s office when you schedule the appointment. Morning draws are most common simply because it’s easier to skip breakfast than to avoid eating all day. Staying well hydrated with water makes the draw itself go more smoothly, since hydration keeps veins easier to find.
Reading Your Results
Lab reports list each measurement alongside a reference range. Falling outside that range doesn’t automatically mean something is wrong. Reference ranges represent roughly 95% of the healthy population, so about 1 in 20 healthy people will have a result that’s technically “abnormal” on any given marker. A single slightly elevated liver enzyme or a marginally low white cell count often just warrants a recheck in a few weeks.
What matters more is the pattern. A low red blood cell count paired with small cell size and low hemoglobin strongly suggests iron-deficiency anemia. Elevated glucose combined with a high HbA1c points clearly toward diabetes. Kidney markers rising together over time tell a different story than one mildly elevated creatinine on a single test. Your provider interprets these results in context, factoring in your symptoms, medications, and medical history, which is why the same number can mean very different things for different people.