Most adults benefit from a core set of blood tests each year: a complete blood count (CBC), a comprehensive metabolic panel (CMP), a lipid panel, and a blood sugar check. Beyond that baseline, your age, sex, and risk factors determine which additional tests make sense. Here’s what each panel actually tells you and when extra screening earns a spot on the list.
The Comprehensive Metabolic Panel
A CMP is the workhorse of annual lab work. It measures 14 substances in a single blood draw and gives your doctor a snapshot of how your major organs are functioning. The panel covers blood sugar (glucose), calcium, four electrolytes (sodium, potassium, bicarbonate, and chloride), two proteins (albumin and total protein), three liver enzymes, bilirubin, and two kidney markers.
The kidney markers, BUN and creatinine, are used to calculate your estimated glomerular filtration rate, or eGFR. That number tells you how well your kidneys are filtering waste. An eGFR below 60 is a sign the kidneys may not be working properly, and a value below 15 indicates kidney failure. The liver enzymes in the panel flag inflammation or damage to liver cells, which can result from medications, alcohol use, fatty liver disease, or infection. Because these problems often produce no symptoms in early stages, catching them on a routine panel is the whole point of yearly testing.
Complete Blood Count
A CBC measures the cells circulating in your blood: red blood cells, white blood cells, and platelets. It’s the primary screening tool for anemia, infection, clotting disorders, and certain blood cancers. Low red blood cell counts or hemoglobin levels suggest anemia, which can cause fatigue and shortness of breath. Elevated white blood cells can signal an active infection or, less commonly, a blood disorder. Platelet counts that are too high or too low affect your blood’s ability to clot. Like the CMP, a CBC is inexpensive, requires no special preparation, and is almost always included in annual lab orders.
Lipid Panel for Heart Health
A lipid panel measures total cholesterol, LDL (“bad”) cholesterol, HDL (“good”) cholesterol, and triglycerides. It’s the primary tool for gauging your cardiovascular risk. For most adults without existing heart disease, the goal is an LDL below 100 mg/dL. If you’re at high risk (a 10% or greater chance of a cardiovascular event over the next 10 years), the target drops to below 70 mg/dL. People who already have heart disease aim for below 55 mg/dL.
You typically need to fast for 10 to 12 hours before a lipid panel, meaning nothing except water. Some newer guidelines allow non-fasting draws for initial screening, but your doctor may still request a fasting sample if your triglycerides come back high or if the results will guide treatment decisions. Cholesterol screening is covered as a preventive service under most insurance plans at no cost to you when done through an in-network provider.
Blood Sugar and Diabetes Screening
There are two common ways to check blood sugar on annual labs. Fasting glucose, which is already part of your CMP, gives a single-moment reading. Hemoglobin A1c (often just called A1c) provides a broader picture by reflecting your average blood sugar over the previous two to three months.
The A1c cutoffs are straightforward:
- Normal: below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or above
The U.S. Preventive Services Task Force recommends diabetes screening for adults aged 35 to 70 who are overweight or obese. Under the Affordable Care Act, this screening is covered at no cost for adults 40 to 70 in that category. If you have a strong family history of diabetes, your doctor may start testing earlier regardless of your weight. An A1c in the prediabetes range is one of the most actionable findings in all of preventive medicine, because lifestyle changes at that stage can delay or prevent progression to full diabetes.
Thyroid Function
A thyroid-stimulating hormone (TSH) test isn’t universally recommended for every adult every year, but it’s frequently included in annual panels, especially for women over 35 and older adults. TSH is the single most sensitive marker for an underactive or overactive thyroid. Normal values generally fall between about 0.5 and 4.5 mU/L, though the upper end of normal shifts upward with age. Adults over 70 may have a TSH as high as 6.0 mU/L without it signaling a problem.
Symptoms of thyroid dysfunction, like unexplained weight changes, fatigue, hair thinning, or feeling unusually cold or warm, overlap with so many other conditions that blood work is often the only reliable way to confirm it. If you have a family history of thyroid disease, or if you’ve had prior abnormal results, annual TSH testing makes clear sense.
Prostate Cancer Screening for Men
The prostate-specific antigen (PSA) test is a blood draw that screens for prostate cancer, but it’s not a blanket recommendation for all men. The U.S. Preventive Services Task Force recommends that men aged 55 to 69 make an individual decision about PSA screening after discussing the potential benefits and harms with their doctor. For men 70 and older, the Task Force recommends against routine PSA screening because the risks of overdiagnosis and unnecessary treatment tend to outweigh the benefits at that age.
The most important risk factors are older age, African American race, and a family history of prostate cancer. Men in these groups may benefit from starting the conversation about screening earlier. Notably, the Task Force does not recommend annual testing even for men who choose to be screened. Screening every two to four years appears to offer a good balance between catching dangerous cancers and avoiding overdiagnosis.
Vitamin D, B12, and Other Add-Ons
Vitamin D testing is one of the most commonly requested add-ons to annual blood work, but it’s not universally recommended. The Task Force has concluded that there isn’t enough evidence to recommend routine vitamin D screening for adults who have no symptoms. That said, if you have bone pain, muscle weakness, dark skin, limited sun exposure, or a condition that affects nutrient absorption, testing is reasonable and your doctor will likely order it.
Vitamin B12 is another test that’s worth discussing if you’re over 65, follow a vegan or vegetarian diet, take long-term acid-reducing medications, or have had weight-loss surgery. Deficiency develops slowly and can cause numbness, memory problems, and fatigue before it’s caught. Neither test is part of a standard panel, but both are simple additions to the same blood draw.
Other Screenings Covered at No Cost
Under the Affordable Care Act, Marketplace plans and many employer plans must cover a range of preventive screenings without copays or deductibles when you use an in-network provider. Beyond cholesterol and diabetes testing, this list includes:
- Hepatitis C screening for adults 18 to 79
- HIV screening for everyone 15 to 65
- Hepatitis B screening for people at high risk, including those born in countries where the virus is more common
- Syphilis screening for adults at higher risk
- Colorectal cancer screening for adults 45 to 75
Most of these aren’t needed annually. Hepatitis C and HIV, for example, may only require a single screening if your risk hasn’t changed. But they’re worth knowing about because they cost you nothing and can catch serious conditions before symptoms appear.
How to Prepare for Your Blood Draw
If your doctor orders a lipid panel or fasting glucose, plan to fast for 10 to 12 hours beforehand. Water is fine and encouraged, since staying hydrated makes your veins easier to find. Black coffee without sugar is usually acceptable, but check with your lab. Schedule your draw for first thing in the morning so you’re not skipping meals well into the afternoon. Most routine panels, including a CBC, CMP, A1c, and thyroid test, can all be drawn from a single tube or two of blood in one visit. Results typically come back within one to three days.