Test Catalog

Test Id : BLACT


Useful For
Suggests clinical disorders or settings where the test may be helpful

Predicting the resistance of beta-lactamase producing isolates to hydrolysis-susceptible beta-lactam antimicrobials

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Name
A short description of the method used to perform the test


NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Beta Lactamase

Lists additional common names for a test, as an aid in searching

Beta Lactamase (Penicillinase)

Lactamase, Beta (Penicillinase)

Penicillinase Activity

Specimen Type
Describes the specimen type validated for testing


Shipping Instructions

For shipping information see Infectious Specimen Shipping Guidelines.

Necessary Information

Specimen source and organism identification are required.


Question ID Description Answers
Q00M0008 Specimen Source (Required) and Organism Identification (Required unless concurrent identification test is ordered)

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Specimen Type: Pure culture of actively growing Enterococcus species, Haemophilus influenzae, Moraxella catarrhalis, Neisseria gonorrhoeae, or Staphylococcus species

Container/Tube: Slant

Specimen Volume: Entire specimen

Collection Instructions: Send specimen in an approved mailing container and label as an etiologic agent/infectious substance.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

See Specimen Required

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Agar plate Reject

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Varies Ambient (preferred)

Useful For
Suggests clinical disorders or settings where the test may be helpful

Predicting the resistance of beta-lactamase producing isolates to hydrolysis-susceptible beta-lactam antimicrobials

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Various bacteria produce a class of enzymes called beta-lactamases, which may be mediated by genes on plasmids or chromosomes. Production of beta-lactamase may be constitutive or induced by exposure to antimicrobials. Beta-lactamases hydrolyze (and thereby inactivate) the beta-lactam rings of a variety of susceptible penicillins and cephalosporins. Beta-lactamases are classified by their preferred antimicrobial substrate and the effect of various inhibitors (such as clavulanic acid) on them.


Some antimicrobials, such as cefazolin and cloxacillin are resistant to such hydrolysis (at least for staphylococcal beta-lactamases).


Beta-lactamase producing strains of the following are resistant to many types of penicillin: Staphylococcus species, Hemophilus influenzae, Neisseria gonorrhoeae, Bacteroides species, Enterococcus species, and Moraxella catarrhalis.


The above organisms, when isolated from critical specimens such as blood or spinal fluid, should always be tested for beta-lactamase production.


Addition of a beta-lactamase inhibitor to a beta-lactam (such as sulbactam plus ampicillin) restores the activity of the antimicrobials.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Negative (reported as positive or negative)

Provides information to assist in interpretation of the test results

A positive test indicates production of beta-lactamase.

Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Some beta-lactamase tests (iodometric and acidometric methods) may not detect certain beta-lactamases.


Many bacteria that do not produce beta-lactamase will be resistant to beta-lactams by other mechanisms.


This test should not be used to detect extended-spectrum beta-lactamases.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Livermore DM, Williams JD: Beta-lactams: mode of action and mechanisms of bacterial resistance. In: Lorian V, ed. Antibiotics in Laboratory Medicine. 4th ed.  Williams and Wilkins; 1996:502-578

2. Gonzalez MD, Ledeboer NA: Haemophilus. In: Carroll KC, Pfaller MA, eds. Manual of Clinical Microbiology. 12th ed. ASM Press; 2019:682-683

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Description
Describes how the test is performed and provides a method-specific reference

A loopful of test organism is placed on a Cefinase disk, which contains the chromogenic cephalosporin, nitrocefin. Beta-lactamase will produce a change from yellow to red within 1 hour and usually within 5 minutes.( Procop, GW, Church DL, Hall GS, et al: Antimicrobial susceptibility testing. In: Koneman's Color Atlas and Textbook of Diagnostic Microbiology. 7th ed. Lippincott, Williams and Wilkins; 2017:chap 17)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Sunday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

1 to 3 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

1 month

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their account representative. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.


LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
BLACT Beta Lactamase 6985-6
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
BLACT Beta Lactamase 6985-6

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | PHP Pdf | CMS Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports