An elevated serum level on a blood test signifies that the concentration of a specific substance is higher than what is typically expected. Serum is the straw-colored liquid portion of the blood that remains after red blood cells, white blood cells, and clotting factors have been removed. This fluid carries various substances throughout the body, including hormones, proteins, electrolytes, and waste products. When a laboratory report indicates an “elevated” result, it means the measured amount of one of these substances falls outside of the standard range of values.
Understanding Blood Serum and Reference Ranges
To perform many blood tests, laboratories separate the liquid component of blood from its solid cells. This is achieved by allowing a blood sample to clot and then spinning it in a centrifuge. The process removes clotting proteins, leaving behind a fluid called serum that contains dissolved substances like nutrients and hormones, making it useful for a wide array of diagnostic tests.
A laboratory test result is interpreted by comparing it to a “reference range.” This range represents the values expected in a healthy population, and an elevated level is a result that is higher than the upper limit of this range. These ranges are not universal, as they can vary significantly from one laboratory to another due to different testing equipment and analytical methods. Furthermore, reference ranges are often specific to an individual’s age and sex.
Common Substances Measured in Serum
A wide variety of substances are measured in serum, providing information about different bodily functions. These tests are often grouped into panels that assess the health of specific organs. For instance, kidney function is evaluated by measuring creatinine and blood urea nitrogen (BUN). Creatinine is a waste product from muscle metabolism, and BUN is a waste product from protein breakdown, so elevated levels can suggest impaired kidney function.
Liver function is assessed by measuring enzymes such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST). These enzymes are contained within liver cells but are released into the bloodstream when liver cells are damaged. Bilirubin, a substance produced from the breakdown of red blood cells and processed by the liver, is another marker that can indicate liver issues if elevated.
Metabolic panels provide a snapshot of a person’s metabolic health by measuring electrolytes and other compounds. Potassium is an electrolyte important for nerve and muscle cell function, including the heart. Calcium is another mineral measured in serum that is involved in bone health, muscle contraction, and nerve signaling. These panels also frequently measure glucose, the primary sugar in the blood, as persistently elevated levels are a hallmark of diabetes mellitus.
Other specialized markers can be measured to investigate specific conditions. C-reactive protein (CRP) is a substance produced by the liver in response to inflammation somewhere in the body. An elevated CRP level is a general marker of an inflammatory process, which could be caused by infection or an autoimmune condition. For men, prostate-specific antigen (PSA), a protein produced by the prostate gland, may be measured, as an elevated level can be associated with prostate enlargement, inflammation, or cancer.
General Causes of Elevated Serum Levels
An elevated reading for a substance in the serum can stem from a wide range of underlying causes, from temporary physiological states to chronic medical conditions. Organ-specific diseases are a common reason for such elevations, as damage can cause substances to build up in the blood. Metabolic disorders are another major category that can lead to abnormal serum levels.
Medications are another frequent contributor to altered lab values. Certain diuretics used to treat high blood pressure can lead to elevated potassium levels, while some cholesterol-lowering drugs can cause an increase in liver enzymes. It is important for individuals to inform their healthcare providers of all medications they are taking, including over-the-counter drugs and supplements.
Lifestyle and environmental factors can also play a part. Dehydration is a common cause of temporarily elevated levels of substances like BUN and creatinine because the concentration of substances in the blood increases when the fluid volume decreases. A diet very high in protein can also raise BUN levels, and strenuous physical activity can cause a temporary increase in creatinine and certain muscle enzymes.
The Role of a Healthcare Provider in Interpretation
An elevated serum level is not a diagnosis. It is a single data point that requires interpretation by a qualified healthcare provider, who evaluates the result’s significance by looking at the complete clinical picture. This includes considering how far outside the reference range the value is, as a slight elevation may be less concerning than a significant one. This result is weighed alongside the patient’s symptoms, medical history, and findings from a physical examination.
A provider will also look at the pattern of results from an entire panel, not just one isolated value. For example, if multiple liver enzymes are elevated, it points more strongly toward a liver issue than if only one value is slightly high. Context is important when interpreting these results.
Based on this assessment, a healthcare provider will determine the appropriate next steps. Often, the first step may be to repeat the test to confirm the result, as temporary factors or lab variability can cause a one-time abnormal reading. If the elevation is confirmed or concerning, further diagnostic testing may be ordered, such as more specialized blood tests, imaging studies like an ultrasound, or a referral to a specialist. The goal is to identify the underlying cause and develop a suitable treatment plan.