82040
Albumin; serum, plasma or whole blood
Albumin is the most abundant protein found in human blood plasma and is synthesized exclusively by the liver. It performs several vital physiological functions, most notably maintaining the oncotic pressure of the vascular system, which prevents fluid from leaking out of the blood vessels into the interstitial spaces. Furthermore, albumin acts as a primary transport protein for various substances, including hormones (like thyroxine), fatty acids, bilirubin, calcium, and many pharmacological agents. The CPT code 82040 represents the laboratory quantitative analysis of albumin in a specimen of serum, plasma, or whole blood. This measurement is an essential component of liver and kidney function assessments. Low levels of albumin, known as hypoalbuminemia, are frequently associated with liver cirrhosis, chronic hepatitis, or malnutrition, reflecting a decrease in protein synthesis. It may also occur in kidney diseases such as nephrotic syndrome, where albumin is lost through the urine, or in malabsorption syndromes such as Crohn's disease. Elevated levels, or hyperalbuminemia, are typically rare and almost exclusively indicative of severe dehydration. The technical procedure for 82040 involves collecting a blood sample via venipuncture, which is then centrifuged to separate the serum or plasma. The analysis is most commonly performed using automated spectrophotometric methods, such as the Bromocresol Green (BCG) or Bromocresol Purple (BCP) colorimetric assays. In these methods, the albumin binds to the dye at an acidic pH, shifting the absorption spectrum and allowing for a quantitative measurement proportional to the concentration of albumin present in the sample. This test provides clinicians with critical data for monitoring nutritional status and assessing the severity of chronic diseases.
Clinical Indications
- Evaluation of liver synthetic function in patients with suspected cirrhosis or hepatitis.
- Assessment of kidney function in patients with edema or proteinuria.
- Screening for protein-calorie malnutrition in elderly or chronically ill patients.
- Monitoring nutritional status in patients receiving parenteral nutrition.
- Investigation of unexplained peripheral edema (swelling).
- Preoperative assessment for major surgical procedures.
- Monitoring of chronic inflammatory conditions or malignancies.
- Evaluation of fluid shifts in patients with congestive heart failure.
Procedure Steps
- Identify the patient using two identifiers and confirm the lab requisition for albumin (82040).
- Perform a standard venipuncture to collect a blood specimen, typically in a serum separator tube (gold top) or a heparinized tube (green top).
- Label the specimen and transport it to the laboratory following standard biohazard protocols.
- Centrifuge the specimen at the required speed and duration to separate the serum or plasma from the cellular components.
- Load the specimen into an automated chemistry analyzer calibrated for albumin quantification.
- The analyzer mixes the sample with a reagent, usually Bromocresol Green (BCG), which binds specifically to albumin.
- Measure the change in light absorbance at a specific wavelength (e.g., 630 nm) using a spectrophotometer.
- Calculate the concentration based on established calibration curves.
- Review the results for accuracy and report the value in g/dL to the ordering clinician.
Coding Guidelines
- 82040 should not be reported separately if the test is performed as part of a Comprehensive Metabolic Panel (80053).
- 82040 is a component of the Hepatic Function Panel (80076); do not unbundle if all panel components are performed.
- If albumin is measured in a source other than serum, plasma, or whole blood (e.g., urine), use a different code such as 82043 (Microalbumin).
- The code 82040 is intended for the total albumin measurement; for albumin-globulin ratio calculation, the total protein (84155) is also required.
- Ensure the diagnosis code (ICD-10) supports the medical necessity of the test for reimbursement.