Why Your Lab Results Don't Always Tell the Whole Story

During your annual physical, your doctor will likely order routine blood tests to help them assess your health.

But bloodwork results are not a diagnosis on their own. Instead, these results help estimate your risk for disease.

Blood test results should be a starting point for conversations with your doctor, said Nathan Razbannia, MD, MPH, a family practice doctor and geriatrician at Cedars-Sinai Primary Care in Marina del Rey. Doctors interpret lab results in conjunction with your symptoms, personal and family medical history, risk factors, age, gender, and even variations in the lab test itself.

“Communication with your doctor is the most important element to interpreting your lab results and making thoughtful decisions that improve your health,” he said. “A ‘good’ cholesterol number doesn’t guarantee someone won’t develop heart disease, just like a higher number doesn’t necessarily mean they will. Prevention is about managing risk—not chasing numbers.”

Here’s how to know what your bloodwork means and how to talk to your doctor about leveraging your tests to improve your health.

Blood Tests Should Be Ordered and Interpreted by Your Doctor

During your annual physical, your doctor will likely order lab work and analyze the results alongside your medical history and symptoms. These standard blood panels do not test for specific conditions but instead provide a snapshot of your biology. The tests often include:

• Complete blood count (CBC), which measures red blood cells, white blood cells and platelets and can help your doctor evaluate you for anemia, infection and inflammation
• Comprehensive metabolic panel (CMP), which provides information about your kidney and liver function and electrolyte, blood sugar and protein levels
• Lipid panel, which measures total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglycerides and can help your doctor gauge your risk for heart disease
• Blood glucose and A1C, which measure your blood sugar levels and can inform your risk for diabetes
• Thyroid-stimulating hormone (TSH), which measures the hormones that regulate your metabolism and can help your doctor screen you for thyroid disorders

Such tests do not reveal the complete scope of your health, which can’t be measured with numbers alone. Doctors evaluate your lab work based on their knowledge of you as a person, including notes from your appointments, trends in your lab results over time and lifestyle factors that may influence your health, Razbannia said.

Patients should always review their tests and ask questions, but addressing a specific lab result is not always about undergoing additional testing.

“Abnormal” and “Normal” Results Are Not the Final Answer

You may receive your lab results in a digital portal, such as My CS-Link. Results list the test, your values, the reference range and whether your numbers are flagged as low or high.

An abnormal lab result is not necessarily an indicator of a significant change in your health. Many lab values fluctuate naturally day by day, and an abnormal blood test result could be caused by dehydration, what you ate, whether you’ve exercised recently or even a laboratory-processing issue.

“Doctors often look for patterns over time rather than reacting to every small change,” Razbannia said. “Before you get fixated on a change, rely on your doctor to interpret it in context and determine the next steps.”

Your doctor will partner with you to address any concerning elevations, focusing on giving you reassurance without subjecting you to unnecessary retesting.

On the flip side, normal blood work doesn't necessarily mean you are not at risk for a specific condition. Your doctor will consider the results alongside your symptoms and risk factors.

“Many conditions are silent and don’t show up on bloodwork,” Razbannia said. “Cholesterol is a factor in cardiovascular health, but not the only factor. So, we take even a ‘good’ result in context as a part of the overall picture for prevention.”

More Testing Isn’t Always Better

After your doctor interprets your bloodwork results, they may order additional or repeat testing. But this is a considered, nuanced decision.

Razbannia cautions patients against self-ordering additional panels without medical guidance. This can be costly and unnecessary and can lead to false alarms, more invasive follow-up procedures, extra radiation and added anxiety.

“Patients should always review their tests and ask questions, but addressing a specific lab result is not always about undergoing additional testing,” he said. “Good healthcare is about ordering the right tests—not every available test. It’s a balance.”

Testing Recommendations Change Based on New Evidence

Medical recommendations evolve as better evidence becomes available. For example, the U.S. Preventive Services Task Force no longer recommends routine urine testing during annual physicals for people without symptoms. Research found that routine urine tests often led to false positives and unnecessary follow-up testing without improving health outcomes.

“Healthcare can evolve,” Razbannia said. “Doctors know when there may be more harm than good to doing a certain test for preventive visits.”

Do Your Research, but Avoid Anxiety

When you get an abnormal test result, it’s natural to seek more information. But online searches, social media and AI can’t make individual recommendations to you based on your history. Use the internet to prepare questions for your doctor, not replace their guidance.

“Medical care can be a deeply emotional process,” Razbannia said. “Looking at things on the internet that may not be verified could cause unwarranted, heightened anxiety. There is too much information on the internet that can’t be relied on for informing coherent decisions.”

Talk to Your Doctor About Your Numbers

If you’re unclear about your tests and what they indicate—especially if the values are critical, you have symptoms or notice unexpected changes—ask your doctor for an explanation. You can ask:

• What changed compared with previous results?
• What does this result mean?
• Are lifestyle changes, medication or follow-up testing recommended?

Conversations don’t always have to focus on abnormal values. Doctors want to talk to you about your health improvements, too.

“We don’t always exchange messages when your results are normal, but when a patient’s cholesterol values improve, I like to acknowledge that their diet and exercise are working,” he said.