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Test Code LDBF Lactate Dehydrogenase (LD), Body Fluid

Reporting Name

Lactate Dehydrogenase (LD), BF

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type

Body Fluid

Necessary Information

Indicate specimen source.

Specimen Required

Collection Container/Tube: Sterile container

Submission Container/Tube: Plastic container

Specimen Volume: 1 mL

Collection Instructions: Centrifuge to remove any cellular material.

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Body Fluid Ambient (preferred) 7 days
  Refrigerated  48 hours

Day(s) and Time(s) Performed

Monday through Sunday; Continuously

Test Classification

This test has been modified from the manufacturer’s instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
LDBF Lactate Dehydrogenase (LD), BF 14803-1


Result ID Test Result Name Result LOINC Value
LD_BF Lactate Dehydrogenase (LD), BF 14803-1
FLD11 Fluid Type 14725-6

Analytic Time

Same day/1 day

Reject Due To


Mild reject; Gross reject







Method Name



If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Test Request Form (T728) with the specimen (

Useful For

Identification of exudative pleural effusions

Clinical Information

Lactate dehydrogenase (LD) activity is present in all cells of the body with highest concentrations in heart, liver, muscle, kidney, lung, and erythrocytes.


Pleural Fluid:

Measurement of LD in body fluids is primarily indicated to aid in the differentiation of transudative and exudative effusions as LD activity is considered an indicator of the extent of inflammation. Dr. Richard Light derived criteria in the 1970s for patients with pleural effusions that are still used today.(1)


The criteria include the measurement of total protein and LD in pleural fluid and serum. Exudates are defined as meeting 1 of the following criteria:

1. Pleural fluid-to-serum protein ratio above 0.5

2. Pleural fluid LD above two-thirds the upper limit of normal serum LD

3. Pleural fluid-to-serum LD ratio above 0.6


Pericardial fluid:

The routine analysis of LD to differentiate exudative and transudative pericardial effusions is not considered helpful.(2)


Peritoneal fluid:

Ascitic fluid LD has reported utility in differentiating secondary bacterial peritonitis from spontaneous bacterial peritonitis when at least 2 of 3 criteria are met in ascites fluid: total protein above 1.0 g/dL, glucose below 50 mg/dL, and LD above the upper reference limit for serum.(3)


Spinal fluid (CSF):

LD is not measured in CSF routinely. Release of LD into CSF occurs as a consequence of cell death. Therefore, LD is a nonspecific marker of cell necrosis and may be raised in a number of pathologic conditions, including meningitis(4) with normal concentrations reported as less than 24 U/L. CSF LDH is also increased in primary brain tumors, central nervous system metastases, hydrocephalus, and cerebral ischemia.


Elevated lactate dehydrogenase in pleural fluid is consistent with exudative effusions.

Clinical Reference

1. Light RW: The Light criteria: the beginning and why they are useful 40 years later. Clin Chest Med 2013 Mar;34(1):21-26

2. Ben-Horin S, Bank I, Shinfeld A, et al: Diagnostic value of the biochemical composition of pericardial effusions in patients undergoing pericardiocentesis. Am J Cardiol 2007 May 1;99(9):1294-1297

3. Soriano G, Castellote J, Alvarez C, et al: Secondary bacterial peritonitis in cirrhosis: a retrospective study of clinical and analytical characteristics, diagnosis and management. J Hepatol 2010;52:39-44

4. Knight JA, Dudek SM, Haymond RE: Early (chemical) diagnosis of bacterial meningitis: cerebrospinal fluid glucose, lactate, and lactate dehydrogenase compared. Clin Chem 1981;27:1431–1434