Gram Stain Evaluation With Sputum Culture Reflex
Use
Evaluate the acceptability of a sputum specimen for aerobic bacterial culture and to determine the extent of culture work-up
Special Instructions
It is strongly recommended that a Gram-stained smear be performed on all expectorated sputa to determine the specimen's acceptability for bacterial culture. Patients should be instructed to remove dentures, rinse mouth, and gargle with water before collecting the specimen to avoid contamination. Specimens should be collected via a deep cough and must be examined to ensure a sufficient quantity of thick mucus, not saliva, is present.
Limitations
An adequate sputum specimen should contain many neutrophils and few to no squamous epithelial cells. A specimen with ≥25 squamous epithelial cells per low power field is considered contaminated and unsuitable for culture. Results obtained from contaminated specimens may be noncontributory or misleading. Culturing expectorated sputum from patients with bacteremia and pneumococcal pneumonia may not always identify the pathogen.
Methodology
Culture-based
Biomarkers
LOINC Codes
- 648-6
- 14328-9
- 14327-1
- 648-6
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Sputum
Volume
5 to 10 mL
Minimum Volume
1 to 2 mL
Container
Sterile screw-cap container
Collection Instructions
The patient should brush his/her teeth and rinse mouth well with water before collecting the specimen to reduce contamination. Only a specimen brought forth by deep cough should be used, ensuring it contains a sufficient amount of thick mucus. Submit only the screw-cap container to the lab.
Patient Preparation
Instruct the patient to remove dentures, rinse mouth, and gargle with water. Ensure deep coughing and collection of sputum, not saliva.
Storage Instructions
Refrigerate at 2°C to 8°C
Causes for Rejection
Unlabeled specimen, inappropriate transport device, leaking specimen, delayed receipt (over 72 hours), poor quality sputum (due to saliva contamination)