Prealbumin

Synonym/Acronym

Transthyretin.

Rationale

To assess nutritional status, monitor total parenteral nutrition, and evaluate liver function toward diagnosis and management of disorders such as malnutrition and chronic kidney disease.

Patient Preparation

There are no fluid, activity, or medication restrictions unless by medical direction. The patient may be instructed to fast prior to the test; protocols vary among facilities.

Normal Findings

Method: Immunoturbidometry.

Age	Conventional Units	SI Units (Conventional Units × 10)
Newborn–1 mo	7–39 mg/dL	70–390 mg/L
1–6 mo	8–34 mg/dL	80–340 mg/L
6 mo–4 yr	11–23 mg/dL	110–230 mg/L
5–15 yr	14–35 mg/dL	140–350 mg/L
16–17 yr	20–43 mg/dL	20–43 mg/L
Adult/older adult	20–42 mg/dL	200–420 mg/L

Critical Findings and Potential Interventions ⬆ ⬇

Overview ⬆ ⬇

Study type: Blood collected in a gold-, red-, or red/gray-top tube; related body system: Digestive, Endocrine, and Immune systems.

Prealbumin is a protein primarily produced by the liver. It is the major transport protein for triiodothyronine and thyroxine. It is also important in the metabolism of retinol-binding protein, which is needed for transporting vitamin A (retinol). Prealbumin has a short biological half-life of 2 days. It is used as an indicator of protein status and a marker for malnutrition. Prealbumin is often measured simultaneously with transferrin and albumin. The role of prealbumin in nutritional management has come into question by some health-care providers (HCPs) because it is a negative acute-phase protein. Prealbumin levels decrease during the acute phase of an inflammatory process such as in burns, infection, tumors, strenuous exercise, surgery, tissue infarction, and trauma, making the use of prealbumin less reliable as a predictor of malnutrition in certain clinical situations. Prealbumin may also be ordered with C-reactive protein to assess for the coexistence of an inflammatory process and provide a more complete interpretation of the results.

Indications ⬆ ⬇

Evaluate nutritional status.

Interfering Factors ⬆ ⬇

Factors That May Alter the Results of the Study

Drugs and other substances that may increase prealbumin levels include anticonvulsants, danazol, oral contraceptives, prednisolone, prednisone, and propranolol.
Drugs and other substances that may decrease prealbumin levels include amiodarone and diethylstilbestrol.

Other Considerations

Reference ranges are often based on fasting populations to provide some level of standardization for comparison. The presence of lipids in the blood may also interfere with the test method; fasting eliminates this potential source of error, especially if the patient has elevated lipid levels.

Potential Medical Diagnosis: Clinical Significance of Results ⬆ ⬇

Increased In

Chronic kidney disease (related to rapid turnover of prealbumin, which reflects a perceived elevation in the presence of overall loss of other proteins that take longer to produce)
Patients receiving steroids (these drugs stimulate production of prealbumin)

Decreased In

Acute-phase inflammatory response (prealbumin is a negative acute-phase reactant protein; levels decrease in the presence of inflammation)
Diseases of the liver (related to decreased ability of the damaged liver to synthesize protein)
Hepatic damage (related to decreased ability of the damaged liver to synthesize protein)
Malnutrition (synthesis is decreased due to lack of proper diet)
Substance use disorder (alcohol) (related to leakage of prealbumin from damaged hepatocytes and/or poor nutrition)
Tissue necrosis (prealbumin is a negative acute-phase reactant protein; levels decrease in the presence of inflammation)

Nursing Implications, Nursing Process, Clinical Judgement ⬆

Before the Study: Planning and Implementation

Teaching the Patient What to Expect

Discuss how this test can assist in assessing nutritional status.
Explain that a blood sample is needed for the test.

After the Study: Implementation & Evaluation Potential Nursing Actions

Treatment Considerations

Instruct the patient to resume usual diet if fasting was required and as directed by the HCP.

Nutritional Considerations

Nutritional therapy may be indicated for patients with decreased prealbumin levels.
Educate the patient, as appropriate, that good dietary sources of complete protein (containing all eight essential amino acids) include meat, fish, eggs, and dairy products, and that good sources of incomplete protein (lacking one or more of the eight essential amino acids) include grains, nuts, legumes, vegetables, and seeds.

Clinical Judgement

Consider how to clearly explain the ramifications of failed lifestyle choices toward overall health including diet and renal function.

Follow-Up and Desired Outcomes

Understands that depending on the results of this procedure, additional testing may be performed to evaluate or monitor disease progression and determine the need for a change in therapy.