Overview
MDL Test Name
Upper Respiratory Culture
MDL Test Code
UR_CULT
Ask at Order Questions
N/A
Specimen Source
Throat swab
Oropharyngeal swab
Nasal swab
Nasopharynx swab
Specimen Requirements
Container/Tube
ESwab
Specimen Volume (minimum)
N/A (swab specimen)
must have swab present in container
Sample Stability Time
48 hours
Transport/Storage Conditions
Refrigerated (2 – 8°C)
Ambient (20 – 25°C)
Patient Preparation / Collection Instructions
Refer to the following MDL guides on MDL’s website:
WSU MDL ESwab General Collection Guide
Performance
Days Performed
Daily; Monday – Sunday
Report Available (TAT) – (Once received at MDL)
3 – 4 days
Specimen Retention Time
7 days
Method Description
Conventional aerobic bacterial culture technique with selective and non-selective media.
Identification methods (when appropriate) may include any of the following: conventional biochemical testing, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, and commercial identification panels.
Susceptibility testing (when appropriate) may include minimal inhibitory concentration (MIC) (broth microdilution or gradient strip diffusion) or disk diffusion.
Reference Values
No pathogens isolated.
Normal Respiratory Flora isolated.
Normal respiratory flora includes:
Viridans Streptococci
nonpathogenic Neisseria
diphtheroids
coagulase-negative Staphylococcus
Rothia
Group F Streptococcus
Anaerobes
Haemophilus species (not influenzae)
Eikenella
Actinobacillus
Capnocytophaga
Morexella
Enterococci
Yeasts (not Cryptococcus)
Insignificant numbers of S. aureus, gram-negative rods, and N. meningitidis
Cautions
Specimens from the upper respiratory tract can be easily obtained but are always contaminated with resident microbiota. Many microorganisms present in the nares and throat are found in both the disease and the carrier states.
Culture of nasopharyngeal specimens to detect carriage of potential pathogens such as Neisseria meningitidis, S. pneumoniae, and H. influenzae should be discouraged. Since these pathogens are all part of the normal oropharyngeal flora, the clinical relevance of culturing them from this site cannot be determined.
Upper respiratory cultures should be done when detection of a specific pathogen is sought and not be performed routinely to detect any organism that is present.