Did Your Doctor Order Blood Work? We Break Down These Common Lab Tests


If you live with diabetes, you may be familiar with routine blood tests that your healthcare team orders periodically.

Blood work provides useful information to guide your diabetes management. These tests may include A1c, regular complete blood counts (CBCs), and occasionally, a comprehensive metabolic panel, sometimes called a CMP for short.

But what exactly is a metabolic panel? What does it measure? And what do the results mean?

Why do I need lab tests for my diabetes care?

You may be asking yourself why lab tests are necessary if you check your blood sugar regularly and there’ve been no significant changes to your health.

Well, lab tests can measure changes in things like electrolytes and organ function years before they ever cause physical symptoms.

As a person living with diabetes, it’s important to catch any issues early, to help prevent long-term diabetes complications. If a lab test result is irregular, your provider can order follow-up tests, refer you to a specialist or order medications to help remedy the issue promptly.

The comprehensive metabolic panel, explained

A comprehensive metabolic panel measures 14 different markers in the body. It is taken at a laboratory and measures the body’s balance of fluids.

It is one of the most commonly ordered tests and is easy to administer. It measures many markers, including the following:


This will measure a snapshot of glucose at the time of the test. This is not, however, equivalent to an A1c test that measures your average blood glucose over the previous three months. If you have diabetes and check your blood sugar often, these results may not be new information for you and your team.


This test captures the balance of electrolytes like sodium, calcium, chloride, carbon dioxide and potassium, which can often fall out of balance if you live with diabetes and have experienced issues such as diabetic ketoacidosis (DKA) or severe dehydration recently. Electrolytes are essential for keeping your blood acidity, also known as pH level, in balance.

Kidney functioning

Your provider will assess kidney functioning by testing blood urea nitrogen (BUN) and creatinine levels. Higher levels of these mean that the kidneys are not fully functioning. This can pose a problem and is important to monitor, especially if you live with diabetes.

Liver functioning

Measuring albumin and total protein in the blood is one way your provider can monitor your liver function. Low levels of either can be seen in people who have existing kidney or liver issues or someone who is struggling to meet their nutritional needs.

The test will also detect levels of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and bilirubin. If any of these levels come back high, this could signal that there’s a problem with liver functioning.

How to prepare

To get the most accurate results, it is suggested that you fast before having your blood drawn for a comprehensive metabolic panel. If you and your healthcare team determine it’s safe for you to fast, you are asked to not eat or drink anything besides water for eight to 12 hours.

If you aren’t clear on whether to fast or how you need to prepare, contact your doctor or the lab facility to review the lab order before the day of the test.

However, you can (and should!) always break a fast to treat a low. It is more important to treat hypoglycemia than worry about a fasting blood test.

It is often suggested to schedule lab work for the morning; this way, your fasting time is when you’re sleeping, and you can eat immediately afterward.

Are there risks?

These blood tests are considered routine and safe and are always taken by a skilled technician.

Since it measures 14 different markers for disease and fluid imbalance, some people may feel slightly lightheaded or faint after the test. There is a small risk of infection at the injection site, but this is exceedingly rare. You may notice a bruise or soreness at the injection site afterward.

Since it requires fasting, there is a risk of low blood sugar before, during and after the test. Make sure to adjust your insulin accordingly, and reach out to your doctor if you have questions about lowering your basal rates or your medication doses to avoid hypoglycemia for a fasting blood draw.

Don’t be afraid to talk to the lab technician beforehand if you experience anxiety or fainting around needles or blood. It doesn’t hurt to pack a snack with you to eat or drink immediately following the blood draw.


A metabolic panel is a very common lab test that helps doctors and healthcare providers assess the state of your health and track changes over time.

While lab tests can seem daunting, they aren’t necessarily a cause for concern.

These snapshots can detect changes in how your organs are functioning early on, to prevent or mitigate the onset of diabetes-related complications.

Getting lab work done and reading lab tests can be stressful and confusing. Don’t be afraid to ask your provider to explain the purpose of the tests they are requesting and what the results mean for your care.

Editor’s note: Educational content related to complications of T2D is made possible with support from Lilly, an active partner of Beyond Type 2 at the time of publication. Editorial control rests solely on Beyond Type 2.