GLBF - Clinical: Glucose, Body Fluid

Test Catalog

Test Name

Test ID: GLBF    
Glucose, Body Fluid

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

Aiding in the diagnosis of infection

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


Blood glucose is measured to assess the glycemic state of a patient. Body fluid glucose concentrations that are lower than expected indicate increased cellularity and, therefore, glycolysis within the body fluid space and serves as an indicator of infection or possibly malignancy. Body fluid glucose concentrations are expected to be lower than that found in serum or plasma. Ideally they are measured in the fasting state whereby glucose is able to equilibrate into the space the body fluid is contained within. 


Pleural fluid:

Low pleural fluid glucose concentrations (<40-60 mg/dL) indicate a complicated parapneumonic or malignant effusion.(1) However, low glucose is not specific for infection or malignancy and may be attributed to hemothorax, tuberculosis, rheumatoid, or lupus pleuritis, among other diseases. pH is the preferred test for making this determination when available.


Pericardial fluid:

Pericardial fluid glucose has been investigated on a limited basis. In presumed normal specimens collected during surgery, pericardial fluid–to-serum ratio for glucose was 1.0 (95% CI, 0.8-1.2).(2)


Peritoneal fluid:

Ascitic fluid glucose should be interpreted in conjunction with serum glucose measurement. In a cohort of noninfected patients with alcohol-related cirrhosis, the mean (SD) ascitic fluid-to-serum glucose ratio was 1.04 (0.25).(3) Ascitic fluid glucose may be helpful in differentiating spontaneous bacterial peritonitis from secondary peritonitis caused by bowel perforation.(4) Secondary peritonitis is likely if 2 of the 3 following criteria are met: 1) total protein >1 g/dL; 2) LDH >225 IU/L (or greater than the upper limit of normal for serum); and 3) glucose <50 mg/dL.(4)


Amniotic fluid:

Amniotic fluid is produced by the amnion and placenta, representing a plasma ultrafiltrate. Amniocentesis may be performed to assess fetal distress. Intraamniotic infection or chorioamnionitis is an acute inflammation of the fetal membranes commonly caused by bacterial infection prompting an inflammatory response leading to labor and term or preterm birth.(5) Chorioamnionitis may be symptomatic (clinical) or asymptomatic (histological) occurring most often during prolonged labor or as a consequence of membrane rupture as bacteria have greater opportunity to ascend the lower genital tract to colonize the uterus. Prompt diagnosis and treatment for clinical chorioamnionitis is critical to avoid maternal and fetal morbidity and mortality. Culture and gram stain are often used in the assessment of infection, however, gram stain lacks sensitivity and culture results are not returned in a timely enough manner to make clinical decisions. Low glucose concentrations have been associated with positive culture results and consequently poor outcomes.(6)


Synovial fluid:

Synovial fluid is present in joint cavities and serves a number of important roles in maintaining joint health and mobility. Symptoms of joint problems include pain, swelling, stiffness, or decreased range of motion. Routine analysis of synovial fluid includes Gram stain, culture, crystal analysis, and cell count with WBC differential. In normal synovial fluid, glucose concentrations are similar to those observed in fasting serum. Low synovial fluid glucose has been associated with septic arthritis or inflammation.(7)

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.

Not applicable

Interpretation Provides information to assist in interpretation of the test results

Pleural fluid:

Glucose <60 mg/dL is typically associated with low fluid pH.  


Pericardial and peritoneal fluids:

Fluid to serum glucose ratio <1.0 may be useful in differentiating infective from parainfective effusions.


Amniotic fluid:

Glucose < 16 mg/dL is associated with positive culture results


Synovial fluid:

Glucose concentrations are typically within 10 mg/dL of fasting plasma glucose concentrations or approximately one-half of the nonfasting plasma glucose concentration.

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

Body fluid glucose results are not diagnostic and should be interpreted in conjunction with other laboratory and clinical findings.


Specimens that have cells present, either due to trauma during collection (blood present) or due to infection (bacteria) that are not centrifuged and separated from cells as soon after collection as possible may have falsely decreased glucose owing to the continued metabolic action of cells in vitro.

Clinical Reference Provides recommendations for further in-depth reading of a clinical nature

1. Light RW: Clinical practice: pleural effusion. N Engl J Med 2002 Jun 20;346(25):1971-1977

2. Ben-Horin S, Shinfeld A, Kachel E, et al: The composition of normal pericardial fluid and its implications for diagnosing pericardial effusions. Am J Med 2005 Jun;118(6):636-640

3. Wilson JA, Suguitan EA, Cassidy WA, et al: Characteristics of ascitic fluid in the alcoholic cirrhotic. Dig Dis Sci 1979 Aug;24(8):645-648

4. Runyon BA, Hoefs JC: Ascitic fluid analysis in the differentiation of spontaneous bacterial peritonitis from gastrointestinal tract perforation into ascitic fluid. Hepatology 1984 May-Jun;4(3):447-450

5. Tita AT, Andrews WW: Diagnosis and management of clinical chorioamnionitis. Clin Perinatol 2010;37:339-354

6. Gonzalez-Bosquet E, Cerquueira MJ, Dominguez C, et al: Amniotic fluid glucose and cytokines values in the early diagnosis of amniotic infection in patients with preterm labor and intact membranes. J Matern Fetal Med 1999;8:155-158

7. Margaretten ME, Kohlwes J, Moore D, Bent S: Does this adult patient have septic arthritis? JAMA 2007;297:1478-1488