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Test Catalog

Test ID: TGLBF    
Triglycerides, Body Fluid

Useful For Suggests clinical disorders or settings where the test may be helpful

Distinguishing between chylous and nonchylous effusions

 

Measurement of triglycerides in body fluids as a surrogate for chylomicrons

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Triglyceride concentration in body fluids is correlated to the presence of chylomicrons and can be useful when diagnosing chylous effusion or differentiating from pseudochylous effusion.(1) Chylous effusions are characterized by the presence of chyle which contains chylomicrons circulating through the lymphatic system. Pseudochylous effusions do not have chylomicrons. These fluids have a milky appearance and can be confused with chylous effusions. While chylous effusions often have elevated triglyceride concentrations and decreased cholesterol concentrations, identification of chylomicrons is considered the gold standard for the diagnosis.

               

Pleural fluid:

Chylothorax is the name given to pleural effusions containing chylomicrons. They develop when chyle accumulates from disruption of the lymphatic system, often the thoracic duct, caused mainly by malignancy or trauma.(1) Lymph contains chylomicron rich chyle characterized by high concentrations of triglycerides. Pseudochylous effusions are the name given to milky appearing effusions that do not contain lymphatic contents but rather form 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.(2) Differentiation of pseudochylothorax from chylothorax is important as their milky or opalescent appearance is similar, however therapeutic management strategies differ.

 

Peritoneal fluid:

Chylous ascites is the name given to peritoneal effusions containing chylomicrons. Obstruction of lymph flow causing leakage from dilated subserosal lymphatics, exudation through the walls of retroperitoneal megalymphatics, and direct leakage of chyle due to a lymphoperitoneal fistula have been proposed as possible mechanisms causing chylous ascites.(3) Elevated triglyceride concentrations have the best correlation with detection of chylomicrons, while cholesterol is not useful at predicting the presence or absence of chylomicrons.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided

Interpretation Provides information to assist in interpretation of the test results

Pleural fluid triglyceride concentrations over 110 mg/dL are consistent with a chylous effusion. Triglyceride concentrations below 50 mg/dL are usually not due to chylous effusions.(1)

 

Peritoneal fluid triglyceride concentrations over 187 mg/dL are most consistent with chylous effusion.(3)

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Dicynone (Etamsylate) at therapeutic concentrations may lead to false-low results.

 

Acetaminophen intoxications are frequently treated with N-acetylcysteine.

 

N-acetylcysteine at a plasma concentration above 166 mg/L and the acetaminophen metabolite, N-acetyl-p-benzoquinone imine (NAPQI) may independently cause falsely low results.

 

In very rare cases, gammopathy, in particular type IgM (Waldenstrom macroglobulinemia), may cause unreliable results.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Hooper C, Lee YC, Maskell N, BTS Pleural Guideline Group: Investigation of a unilateral pleural effusion in adults: British Thoracic Society Pleural Disease Guideline 2010. Thorax. 2010;65(Suppl2):ii4-17. doi: 10.1136/thx.2010.136978

2. Staats BA, Ellefson RD, Budahn LL, et al: The lipoprotein profile of chylous and nonchylous pleural effusions. Mayo Clin Proc. 1980;55(11):700-704

3. Thaler MA, Bietenbeck A, Schulz C, Luppa PB: Establishment of triglyceride cut-off values to detect chylous ascites and pleural effusions. Clin Biochem. 2017 Feb;50(3):134-138. doi: 10.1016/j.clinbiochem.2016.10.008

4. McGrath EE, Blades Z, Anderson PB:Chylothorax: aetiology, diagnosis, and therapeutic options. Respir Med. 2010 Jan;104(1):1-8. doi: 10.1016/j.rmed.2009.08.010