Table 22.

Laboratory Diagnosis of Infections of the Pleural Space

Etiologic Agents	Diagnostic Procedures	Optimum Specimens	Transport Issues and Optimal Transport Time
Bacteria
Aerobes
Staphylococcus aureus	Gram stain Culture	Pleural fluid	Sterile container, RT, 2 h; 4°C, >2–24 h
Streptococcus pneumoniae	As above, plus S. pneumoniae urinary antigen	Urine, pleural fluid	Sterile container, RT, 24 h; >24 h–14 d, 2°C –8°C; Sterile container, RT, 2 h; 4°C, >2–24 h
Streptococcus pyogenes    Streptococcus anginosus group   Enteric gram-negative bacilli   Enterococcus spp   Pseudomonas aeruginosa	Gram stain Culture	Pleural fluid	Sterile container, RT, 2 h; 4°C, >2–24 h
Nocardia	Gram stain Modified acid-fast stain Culture (include selective BCYE or other selective media)
Legionella	Gram stain—carbolfuchsin counter stain Culture on BCYE	Pleural fluid	Sterile container, RT, 2 h; 4°C, >2–24 h
	Legionella urinary antigen (L. pneumophila serogroup 1 only)	Urine	Sterile container, RT, <24 h; 4°C, >24 h–14 d
Anaerobes
Bacteroides fragilis group   Prevotella spp   Fusobacterium nucleatum   Peptostreptococcus   Actinomyces spp	Gram stain Anaerobic culture	Pleural fluid	Anaerobic transport vial, RT, 72 h; without transport RT ≤60 min
Mycobacteria
Mycobacterium tuberculosis	Acid-fast stain Mycobacterial culture NAATa	Pleural fluid	Sterile container, RT, 2 h; 4°C, >2–24 h
	Histology	Pleural or lung biopsy Pleural fluid	Sterile container, RT, 2 h; 4°C, 3 d Formalin container, RT, 2–14 d
Fungi
Fungi	Fungal stain—calcofluor-KOH; other fungal stains Fungal culture	Pleural fluid Pleural biopsy required for some diseases	Sterile container, RT, 2 h; 4°C, >2–24 h
Candida spp	As above plus may be evident on Gram stain	Pleural fluid	Sterile container, RT, 2 h; 4°C, >2–24 h
Aspergillus	General fungal assays (ie, stains, culture, serology) plus galactomannan, (1–3)-β-d-glucanb	BAL	Sterile container, 4°C, ≤5 d; –70°C >5 d
		Serum	Clot tube RT, 2 d; 4°C
Histoplasma capsulatum	Fungal stain—calcofluor-KOH; other fungal stains Fungal culture Histology	Pleural fluid	Sterile container, RT, 2 h; 4°C, >2–24 h
		Pleural biopsy	Sterile container, RT, 2 h; 4°C, >2–24 h; formalin container for histology, RT 2–14 d
	Antigen testc	Serum, urine, BAL, pleural fluid	Clot tube, RT, 2 d; 4°C, 2–14 d Sterile container (urine and fluid), RT 2 h; >2–72 h, 4°C
	Serum antibody (complement fixation)	Serum	Clot tube RT, 2 d; 4°C, 2–14 d
Coccidioides immitis/posadasii	General fungal assays (ie, stains, culture, serology) plus histology	Pleural fluid Pleural biopsy	Sterile container, RT, 2 h; 4°C, >2–24 h
	Serum antibody IgM (ID, LA, EIA) IgG antibody (complement fixation, EIA)	Serum	Clot tube, RT, 2 d; 4°C, 2–14 d
Blastomyces dermatitidis	Fungal stains and cultures (but not serology) plus histology	Pleural fluid Pleural biopsy	Sterile container, RT, 2 h; 4°C, >2–24 h
	Antigen testc	Urine, BAL, pleural fluid, serum	4°C, ≤5 d
Parasites
Paragonimus westermani   Entamoeba histolytica   Echinococcus   Toxoplasma gondii	Direct microscopic examination of pleural fluid and sputum for characteristic ova Direct examination of pleural fluid for troph and cyst forms Direct examination of pleural fluid for scolices Giemsa-stained smear of pleural fluid or pleural biopsy	Pleural fluid Sputum Pleural fluid	Sterile container, fresh samples 4°C, 60 min; RT, preserved samples >60 min–30 d

Abbreviations: BAL, bronchoalveolar lavage; BCYE, buffered charcoal yeast extract; EIA, enzyme immunoassay; ID, immunodiffusion; IgG, immunoglobulin G; IgM, immunoglobulin M; KOH, potassium hydroxide; LA, latex agglutination; NAAT, nucleic acid amplification test; RT, room temperature.

^aNo US Food and Drug Administration–cleared test is currently available. Availability is laboratory specific. Provider needs to check with the laboratory for optimal specimen source, performance characteristics and turnaround time.

^bPerformance characteristics of these tests are reviewed in references [133, 134].

^cMay cross-react with other endemic mycoses.