Important Information about Monkeypox from NC-DHHS (5/20/2022) to All North Carolina Clinicians and Laboratorians

Respiratory Cultures: Screening Criteria

Sputum and Tracheal Aspirate specimens are subject to screening for specimen acceptibility, including those from Transplant patients. Unacceptable specimens are rejected for culture, and the results of the unacceptable screening smears are called to the ordering physician, or to the patient's nurse. Specimens from Transplant patients are not rejected, but are reported with the comment "Smear Results Suggest Poor Specimen Quality".

To increase the likelihood of obtaining an acceptable specimen, please review Sputum Collection Methods prior to obtaining specimen.

The following criteria are used to determine acceptance or rejection, using a Gram-stained smear of the specimen:

PMN/Low Power Field Squamous Epithelial Cells/Low Power Field Acceptable? Comments
<10 <10 NO
Gram-stain does not suggest ongoing inflammatory process; Specimen processed by request only for neutropenic patients (ANC <0.5).
10-25 <10 YES
>25 <10 YES
>25 10-25 YES
If No Organisms are Seen (on Oil Immersion) the
Ordering Physician or Nurse is contacted: Specimen is Unacceptable due to Low Culture Yield.
If yeast are the only organisms observed (on oil immersion) the ordering physician is contacted to determine need for culture.

Tracheal Aspirate
Adult Patients
(>16 y)
No Organisms Seen on Oil Immersion
Yeast Only Seen on Smear
>10 Squamous Epithelial Cells/LPF

<10 Epithelial Cells/LPF

Pediatric Patients
(<16 y)

No Organisms Seen on Oil Immersion
Yeast Only Seen on Smear



Any Squamous Epithelial Cells/LPF


Reviewed by Christopher Parker on December 08, 2021

Note: Reference ranges provided on this web site are for guidance only, and may not reflect the most recent changes. Refer to laboratory reports for current reference data.

UNC Hospitals
McLendon Clinical Laboratories
101 Manning Drive
Chapel Hill, NC 27514