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HelpTest Code CHLBF Cholesterol, Body Fluid
Reporting Name
Cholesterol, BFUseful For
Aiding in the diagnosis of a cholesterol effusion or cholesterol-rich pseudochylous effusion in body fluids
Distinguishing between chylous and pseudochylous pleural effusions
Distinguishing between malignant and nonmalignant ascites
Method Name
Colorimetry
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Body FluidOrdering Guidance
This test provides a measurement of cholesterol in body fluids, which is useful for screening of a cholesterol effusion or cholesterol-rich pseudochylous effusion. To distinguish between chylous and nonchylous effusions, order BFLA1 / Lipid Analysis, Body Fluid; which measures cholesterol and triglyceride concentrations, as well as chylomicrons and plasma lipoproteins.
Necessary Information
1. Date and time of collection are required.
2. Specimen source is required.
Specimen Required
Preferred Source:
-Peritoneal fluid (peritoneal, abdominal, ascites, paracentesis)
-Pleural fluid (pleural, chest, thoracentesis)
-Drain fluid (drainage, JP drain)
-Pericardial fluid
Acceptable Source: Write in source name with source location (if appropriate)
Collection Container/Tube: Sterile container
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Centrifuge to remove any cellular material and transfer into a plastic vial.
2. Indicate the specimen source and source location on label.
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Body Fluid | Frozen (preferred) | 30 days | |
| Refrigerated | 7 days | ||
| Ambient | 24 hours |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | Reject |
| Anticoagulant or additive Amniotic fluid Breast milk Saliva Nasal secretions Sputum Synovial fluid Bronchoalveolar lavage (BAL) or bronchial washings Colostomy/ostomy Feces Spinal fluid Gastric secretions Urine Vitreous fluid | Reject |
Reference Values
An interpretive report will be provided.
Day(s) Performed
Monday through Sunday
CPT Code Information
84311-Spectrophotometry, analyte not specified (cholesterol)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CHLBF | Cholesterol, BF | 12183-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| FLD25 | Fluid Type: | 14725-6 |
| BFCHL | Cholesterol (BF) | 12183-0 |
Clinical Information
Serum cholesterol is measured to determine the concentration of circulating lipoprotein particles when screening for cardiovascular disease. The concentration is affected by genetic and lifestyle factors. Cholesterol concentrations in serous effusions increase due to exudative processes that cause cell lysis or increased vascular permeability. Measurement of cholesterol in body fluids is used for the diagnosis of a cholesterol effusion or cholesterol-rich pseudochylous effusion. Pseudochylous effusions contain low triglycerides and high cholesterol and occur from chronic pleural effusions such as rheumatic pleurisy and tuberculosis. Malignant effusions may become enriched with cholesterol due to increased synthesis and release from neoplastic cells or lymphatic obstruction.(1)
Pleural fluid:
Chylothorax is the name given to pleural effusions containing chylomicrons with accordingly high triglyceride and low cholesterol concentrations, which occurs when chyle accumulates from a disruption of the thoracic duct caused mainly by malignancy or trauma.(2)
Pseudochylous effusions accumulate gradually through the breakdown of cellular lipids in long-standing effusions such as rheumatoid pleuritis, tuberculosis, or myxedema, and by definition the effluent contains high concentrations of cholesterol, while chylous effusions contain high concentrations of triglycerides in the form of chylomicrons.(3)
Differentiation of pseudochylothorax from chylothorax is important as their milky or opalescent appearance is similar; however, therapeutic management strategies differ.
Measurement of pleural fluid cholesterol has also been investigated in multiple studies for the purpose of differentiating exudates from transudates.(4) Most of these studies concluded that cholesterol performs as well as measurement of lactate dehydrogenase and total protein applying Light's criteria, but does not add much value beyond that.
Peritoneal fluid:
Ascites is the pathologic accumulation of excess fluid in the peritoneal cavity. Cholesterol analysis in peritoneal fluid may be a useful index to separate malignant ascites from nonmalignant, often cirrhotic ascites. Studies report concentrations ranging from greater than 32 to 70 mg/dL are greater than 88% sensitive and greater than 80% specific for malignant ascites, outperforming cytology.(4)
Interpretation
Pleural fluid cholesterol concentrations between 46 to 65 mg/dL are consistent with exudative effusions. Cholesterol concentrations above 200 mg/dL suggest a pseudochylous effusion.(2)
Peritoneal fluid cholesterol concentrations between 33 to 70 mg/dL suggest a malignant cause of ascites.(4)
Cautions
In very rare cases, gammopathy, in particular type IgM (Waldenstrom macroglobulinemia), may cause unreliable results.
Acetaminophen intoxications are frequently treated with N-acetylcysteine.
N-acetylcysteine, at the therapeutic concentration when used as an antidote, and the acetaminophen metabolite N-acetyl-p-benzoquinone imine (NAPQI), may independently cause falsely low results.
Method Description
Cholesterol is measured by an automated enzymatic method. The reagents include cholesterol ester hydrolase, cholesterol oxidase, and a coupled colorimetric end-point chemistry system.(Package insert: Roche Cholesterol Reagent, c501. Roche Diagnostics Corp; V 16.0, 10/2023)