Lab Test

Serum Albumin Ascites Gradient

Test Codes

EPIC: LAB5004, ALBGR

Specimen Collection Criteria

Collect: Blood AND Ascitic Fluid. 

  • Blood: One Gold-top SST tube. (Minimum Whole Blood: 4.0 mL)
  • Fluid: Ascitic fluid in a sterile collection container, syringe, or Vacutainer® tube without additive. (Minimum: 1.0 mL)
  • Serum and ascitic fluid samples should be collected on the same day. 

Physician Office/Draw Specimen Preparation

  • Blood: Let specimens clot 30-60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged SST tube within two hours of collection. 
  • Fluid: Maintain specimen refrigerated (2-8°C or 36-46°F) prior to transport. Room temperature is acceptable for a maximum of 2 hours. 

Preparation for Courier Transport

Transport: Centrifuged SST tube and fluid specimen, refrigerated (2-8°C or 36-46°F). (Minimum: 0.5 mL serum and 1.0 mL fluid)

Rejection Criteria

  • Moderate to grossly hemolyzed specimens. 
  • Red-top tubes with serum not separated from cells within two hours of collection.
  • Fluid specimens collected in a container or tube with an additive. 
  • A pathologist will be consulted when the collection of fluid and serum samples differ by more than two hours. 

In-Lab Processing

Centrifuge fluid specimens immediately to remove cellular material. Let SST specimens clot 30-60 minutes then immediately centrifuge to separate serum from cells. Deliver immediately to the appropriate testing station.

Storage

Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers® with Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers® without Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 7 days

Fluid Specimens
Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Undetermined

Specimen Storage in Department Prior to Disposal:

Serum: Refrigerated (2-8°C or 36-46°F): 7 days
Fluid: Refrigerated (2-8°C or 36-46°F): 30 days 

Laboratory

Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory
Grosse Pointe Chemistry Laboratory
Royal Oak Automated Chemistry Laboratory
Troy Chemistry Laboratory 

Performed

Sunday – Saturday, 24 hours a day.
Results available within 4 hours. 

Reference Range

A serum ascites albumin gradient ≥ 1.1 g/dL indicates portal hypertension.

Test Methodology

Spectrophotometry.

Interpretation

The gradient is calculated by subtracting the ascitic fluid albumin concentration from a serum albumin drawn at a similar time.

Clinical Utility

A serum ascites albumin gradient ≥ 1.1 g/dL is consistent with portal hypertension from causes such as cirrhosis, congestive heart failure, or portal vein thrombosis.

A low gradient (less than 1.1 g/dL) occurs in conditions such as peritoneal carcinomatosis, peritoneal tuberculosis, pancreatitis, serositis, and nephrotic syndrome.

In the past a value of ≥ 1.1 g/dL was interpreted as a transudate, and if < 1.1 g/dL the fluid was interpreted as an exudate.

CPT Codes

82040, 82042.

Contacts

Last Updated

4/16/2021

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