ALB

A gene on chromosome 4q13.3 that encodes albumin, the soluble, monomeric protein that comprises the protein in the serum. It serves as a carrier protein for steroids, fatty acids and thyroid hormones; binds well to water, Ca2+, Na2+, K+, fatty acids, hormones, bilirubin and certain drugs; and plays a central role in stabilising extracellular fluid volume. It is produced in the liver as preproalbumin and partially cleaved before its release from the rough endoplasmic reticulum.
Molecular pathology
ALB mutations cause familial dysalbuminemic hyperthyroxinaemia.

Albumin and Albumin/Globulin Ratio

Synonym/acronym: Alb, A/G ratio.

Common use

To assess liver or kidney function and nutritional status.

Specimen

Serum (1 mL) collected in a gold-, red-, or red/gray-top tube. Plasma (1 mL) collected in a green-top (heparin) tube is also acceptable.

Normal findings

(Method: Spectrophotometry) Normally the albumin/globulin (A/G) ratio is greater than 1.

Age	Conventional Units	SI Units (Conventional Units × 10)
Cord	2.8–4.3 g/dL	28–43 g/L
Newborn–7 d	2.6–3.6 g/dL	26–36 g/L
8–30 d	2–4.5 g/dL	20–45 g/L
1–3 mo	2–4.8 g/dL	20–48 g/L
4–6 mo	2.1–4.9 g/dL	21–49 g/L
7–12 mo	2.1–4.7 g/dL	21–47 g/L
1–3 yr	3.4–4.2 g/dL	34–42 g/L
4–6 yr	3.5–5.2 g/dL	35–52 g/L
7–19 yr	3.7–5.6 g/dL	37–56 g/L
20–40 yr	3.7–5.1 g/dL	37–51 g/L
41–60 yr	3.4–4.8 g/dL	34–48 g/L
61–90 yr	3.2–4.6 g/dL	32–46 g/L
Greater than 90 yr	2.9–4.5 g/dL	29–45 g/L

Description

Most of the body’s total protein is a combination of albumin and globulins. Albumin, the protein present in the highest concentrations, is the main transport protein in the body for hormones, therapeutic drugs, calcium, magnesium, heme, and waste products such as bilirubin. Albumin also significantly affects plasma oncotic pressure, which regulates the distribution of body fluid between blood vessels, tissues, and cells. Albumin is synthesized in the liver. Low levels of albumin may be the result of either inadequate intake, inadequate production, or excessive loss. Albumin levels are more useful as an indicator of chronic deficiency than of short-term deficiency. Hypoalbuminemia or low serum albumin, a level less than 3.4 g/dL, can stem from many causes and may be a useful predictor of mortality. Normally albumin is not excreted in urine. However, in cases of kidney damage some albumin may be lost due to decreased kidney function as seen in nephrotic syndrome, and in pregnant women with pre-eclampsia and eclampsia.

Albumin levels are affected by posture. Results from specimens collected in an upright posture are higher than results from specimens collected in a supine position.

The albumin/globulin (A/G) ratio is useful in the evaluation of liver and kidney disease. The ratio is calculated using the following formula:

albumin/(total protein – albumin)

where globulin is the difference between the total protein value and the albumin value. For example, with a total protein of 7 g/dL and albumin of 4 g/dL, the A/G ratio is calculated as 4/(7 – 4) or 4/3 = 1.33. A reversal in the ratio, where globulin exceeds albumin (i.e., ratio less than 1.0), is clinically significant.

This procedure is contraindicated for

N/A

Indications

Assess nutritional status of hospitalized patients, especially geriatric patients
Evaluate chronic illness
Evaluate liver disease

Potential diagnosis

Increased in

Any condition that results in a decrease of plasma water (e.g., dehydration); look for increase in hemoglobin and hematocrit. Decreases in the volume of intravascular liquid automatically result in concentration of the components present in the remaining liquid, as reflected by an elevated albumin level.
Hyperinfusion of albumin

Decreased in

Insufficient intake:

Malabsorption (related to lack of amino acids available for protein synthesis)
Malnutrition (related to insufficient dietary source of amino acids required for protein synthesis)

Decreased synthesis by the liver:

Acute and chronic liver disease (e.g., alcoholism, cirrhosis, hepatitis) (evidenced by a decrease in normal liver function; the liver is the body’s site of protein synthesis)
Genetic analbuminemia (related to genetic inability of liver to synthesize albumin)

Inflammation and chronic diseases result in production of acute-phase reactant and other globulin proteins; the increase in globulins causes a corresponding relative decrease in albumin:

Amyloidosis
Bacterial infections
Monoclonal gammopathies (e.g., multiple myeloma, Waldenström’s macroglobulinemia)
Neoplasm
Parasitic infestations
Peptic ulcer
Prolonged immobilization
Rheumatic diseases
Severe skin disease

Increased loss over body surface:

Burns (evidenced by loss of interstitial fluid albumin)
Enteropathies (e.g., gluten sensitivity, Crohn’s disease, ulcerative colitis, Whipple’s disease) (evidenced by sensitivity to ingested substances or related to inadequate absorption from intestinal loss)
Fistula (gastrointestinal or lymphatic) (related to loss of sequestered albumin from general circulation)
Hemorrhage (related to fluid loss)
Kidney disease (related to loss from damaged renal tubules)
Pre-eclampsia (evidenced by excessive renal loss)
Rapid hydration or overhydration (evidenced by dilution effect)
Repeated thoracentesis or paracentesis (related to removal of albumin in accumulated third-space fluid)

Increased catabolism:

Cushing’s disease (related to excessive cortisol induced protein metabolism)
Thyroid dysfunction (related to overproduction of albumin binding thyroid hormones)

Increased blood volume (hypervolemia):

Congestive heart failure (evidenced by dilution effect)
Pre-eclampsia (related to fluid retention)
Pregnancy (evidenced by increased circulatory volume from placenta and fetus)

Critical findings

N/A

Interfering factors

Drugs that may increase albumin levels include carbamazepine, furosemide, phenobarbital, and prednisolone.
Drugs that may decrease albumin levels include acetaminophen (poisoning), amiodarone, asparaginase, dextran, estrogens, ibuprofen, interleukin-2, methotrexate, methyldopa, niacin, nitrofurantoin, oral contraceptives, phenytoin, prednisone, and valproic acid.
Availability of administered drugs is affected by variations in albumin levels.

Nursing Implications and Procedure

Pretest

Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
Patient Teaching: Inform the patient this test can assist with evaluation of liver and kidney function, as well as chronic disease.
Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex. The patient should be assessed for signs of edema or ascites.
Obtain a history of the patient’s gastrointestinal, genitourinary, and hepatobiliary systems; symptoms; and results of previously performed laboratory tests and diagnostic and surgical procedures.
Obtain a list of the patient’s current medications including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
Review the procedure with the patient. Inform the patient that specimen collection takes approximately 5 to 10 min. Address concerns about pain and explain that there may be some discomfort during the venipuncture.
Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
Note that there are no food, fluid, or medication restrictions unless by medical direction.

Intratest

Potential complications: N/A
Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
Instruct the patient to cooperate fully and to follow directions. Direct the patient to breathe normally and to avoid unnecessary movement.
Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection. Perform a venipuncture.
Remove the needle and apply direct pressure with dry gauze to stop bleeding. Observe/assess venipuncture site for bleeding or hematoma formation and secure gauze with adhesive bandage.
Promptly transport the specimen to the laboratory for processing and analysis.

Post-Test

Inform the patient that a report of the results will be made available to the requesting health-care provider (HCP), who will discuss the results with the patient.
Nutritional Considerations: Dietary recommendations may be indicated and will vary depending on the severity of the condition. Ammonia levels may be used to determine whether protein should be added to or reduced from the diet.
Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP. Recognize anxiety related to test results and answer any questions or address any concerns voiced by the patient or family.
Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Availability of administered drugs is affected by variations in albumin levels. Patients receiving therapeutic drug treatments should have their drug levels monitored when levels of the transport protein, albumin, are decreased in order to prevent development of toxic drug concentrations. Evaluate test results in relation to the patient’s symptoms and other tests performed.

Related Monographs

Related tests include ALT, ALP, ammonia, anti–smooth muscle antibodies, AST, bilirubin, biopsy liver, CBC hematocrit, CBC hemoglobin, CT biliary tract and liver, GGT, hepatitis antibodies and antigens, KUB studies, laparoscopy abdominal, liver scan, MRI abdomen, osmolality, potassium, prealbumin, protein total and fractions, radiofrequency ablation liver, sodium, US abdomen, and US liver.
See the Gastrointestinal, Genitourinary, and Hepatobiliary systems tables at the end of the book for related tests by body system.

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