Diagnostic value of pleural fluid obtained from a chest tube collection system.
BACKGROUND
Pleural fluid is typically drawn directly from the pleural space for diagnostic studies, but occasionally analyses are desired when a chest tube is already in place and a traditional approach is not feasible. The diagnostic value of analyzing fluid samples obtained from the pleural fluid collection system after chest tube insertion is unknown.


METHODS
We performed a prospective observational study of patients in whom chest tube placement was planned for clinical indications. Diagnostic studies were performed on fluid obtained from the pleural space at the time of tube insertion and then repeated 2, 6, and 24 h later on samples obtained from the fluid collection system.


RESULTS
Fifty-five percent of the 23 effusions studied met light's criteria for exudate at baseline. Lactate dehydrogenase (LDH) varied considerably over time from baseline measures with only 25 % of measures at 24 h falling within 25 % of baseline levels. The sensitivity for exudate by LDH remained 100 % with poor specificity ranging 50-69 % with repeat measures. Total protein exhibited less variability with 85 % of measures at 24 h falling within 25 % of baseline measure. Sensitivity and specificity at 24 h were 88 and 82 %, respectively. Repeat measures of cholesterol, albumin, and triglycerides generally correlated well (Spearman's rho > 0.90) with baseline values. Measures of glucose and cell counts varied considerably from baseline.


CONCLUSIONS
Analysis of pleural fluid from a chest tube collection system is feasible and can provide useful diagnostic information. Practitioners should consider the test characteristics of each measure when interpreting samples obtained.
Division of Pulmonary and Critical Care Medicine, University of Maryland School of Medicine, 110 South Paca Street, 2nd Floor, Baltimore, MD, 21201, USA, rreed@medicine.umaryland.edu.
Robert M
RM
Reed
Michael
M
Eberlein
Giora
G
Netzer
Edward
E
Pickering
Carl
C
Shanholtz
Avelino C
AC
Verceles
Michael T
MT
McCurdy
D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D015505:Chest Tubes; D002784:Cholesterol / Q000378:metabolism; D005122:Exudates and Transudates / Q000378:metabolism*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000175:diagnosis* / Q000209:etiology / Q000378:metabolism; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D015203:Reproducibility of Results; D012709:Serum Albumin / Q000378:metabolism; D000075462:Serum Albumin, Human; D013048:Specimen Handling / Q000295:instrumentation*; D013997:Time Factors; D014280:Triglycerides / Q000378:metabolism
C422455:ALB protein, human; D015415:Biomarkers; D012709:Serum Albumin; D014280:Triglycerides; D002784:Cholesterol; D007770:L-Lactate Dehydrogenase; D000075462:Serum Albumin, Human