ESBL – Extended Spectrum beta-lactamase – Confirmation

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Specimen Collection and Handling

Specimen Requirements

Test Requested Required Requisition(s) Specimen Type Minimum Volume Collection Kit

Extended Spectrum beta-lactamase confirmation

Pure viable subculture of organism on appropriate  medium (Columbia sheep blood agar plate) or a swab of a pure subculture of the organism in amies transport medium



Submission and Collection Notes


Specimen Type: Pure viable subculture of 24 – 48 hours growth of organism on an appropriate medium or a swab for ESBL screen test


Note: if a swab or broth is received the TAT will be delayed by at least 24 hours.

NB: Primary cultures are unacceptable as they should be processed in the originating lab. The submitter will be contacted by telephone. A report will be issued to indicate that the test has been rejected.

Storage and Transport

Label the specimen with at least 2 identifiers and place in a biohazard bag and seal.

Special Instructions

NB: Culture must be viable. Use a fresh subculture and ship in conditions to ensure viability on receipt.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

ESBL confirmation testing is performed daily.

Turnaround time is up to 3 days.

Test Methods

ESBL confirmation is performed only on Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, and Proteus mirabils.

Isolates are confirmed for ESBL using conventional method recommended by Clinical Laboratory Standards Institute (CLSI).


Results are reported to the ordering physician or health care provider as indicated on the requisition.


LAB-SD-125, Reference Bacteriology and Antimicrobial Susceptibility: New Requisition and Testing Algorithm for Improved Test Utilization

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Updated 25 Sep 2019