Test Id : HELIS

When this test is ordered, the reflex tests may be performed at an additional charge.

When Helicobacter pylori is isolated, identification will be confirmed, and susceptibility testing performed. The routine susceptibility panel includes amoxicillin, clarithromycin, levofloxacin, metronidazole, rifampin, and tetracycline.

If an isolate of H pylori does not grow for susceptibility testing, additional testing for H pylori with clarithromycin resistance prediction may be performed.

For test utilization options, see Helicobacter pylori Diagnostic Algorithm.

Specimen must be received in laboratory within 48 hours of collection. Specimen should be collected and packaged as close to shipping time as possible.

Specimen source is required; include the specific anatomic source.

Preferred:

Specimen Type: Fresh tissue or biopsy

Sources: Gastric

Container/Tube: Sterile container

Specimen Volume: 0.5 x 0.2 x 0.2-cm sized piece of tissue

Collection Instructions: Acquire biopsied tissue; moisten with sterile saline

Acceptable:

Specimen Type: Fluid

Sources: Gastric brushings, gastric aspirate

Container/Tube: Sterile container

Specimen Volume: Entire collection or 0.5 mL

Specimen Type: Fresh tissue or biopsy

Sources: Duodenum

Container/Tube: Sterile container

Specimen Volume: 0.5 x 0.2 x 0.2-cm sized piece of tissue

Collection Instructions: Acquire biopsied tissue; moisten with sterile saline

• Helicobacter pylori Diagnostic Algorithm

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Microbiology Test Request (T244)

-Gastroenterology and Hepatology Test Request (T728)

See Specimen Required

Recovery of Helicobacter pylori from gastric specimens for antimicrobial susceptibility testing of the organism (amoxicillin, clarithromycin, levofloxacin, metronidazole, rifampin, and tetracycline are routinely tested)

When this test is ordered, the reflex tests may be performed at an additional charge.

When Helicobacter pylori is isolated, identification will be confirmed, and susceptibility testing performed. The routine susceptibility panel includes amoxicillin, clarithromycin, levofloxacin, metronidazole, rifampin, and tetracycline.

If an isolate of H pylori does not grow for susceptibility testing, additional testing for H pylori with clarithromycin resistance prediction may be performed.

Helicobacter pylori is a spiral-shaped gram-negative bacterium that may cause chronic gastritis, peptic ulcer disease, or gastric neoplasia. In adults of industrialized countries, an estimated 0.5% of the susceptible population becomes infected each year, although the incidence has been decreasing over time. The organism may asymptomatically colonize humans.

In suspected H pylori-associated disease, the H pylori with clarithromycin resistance prediction polymerase chain reaction (PCR) test or urea breath test is recommended for patients younger than 60 years old without alarming signs and symptoms (see Helicobacter pylori Diagnostic Algorithm). If clarithromycin resistance is predicted by the PCR test, endoscopy with biopsy should be considered for H pylori culture with antimicrobial susceptibility testing. For those 60 years old or older who have alarming signs and symptoms, endoscopy with biopsy is recommended, with consideration for H pylori culture with antimicrobial susceptibility testing on the gastric biopsy. If patients fail to respond to treatment, endoscopy with biopsy should be considered for H pylori culture with antimicrobial susceptibility testing.

The Clinical and Laboratory Standards Institute (CLSI) recommends agar dilution for H pylori antimicrobial susceptibility testing. Amoxicillin, clarithromycin, levofloxacin, metronidazole, rifampin, and tetracycline are routinely tested. CLSI has defined interpretive categories for clarithromycin. The antimicrobials for which the European Committee on Antimicrobial Susceptibility Testing defines interpretive categories include amoxicillin, clarithromycin, levofloxacin, metronidazole, rifampin, and tetracycline.

No growth of Helicobacter pylori

Susceptibility results are reported as minimal inhibitory concentration (MIC) in mcg/mL. Breakpoints (also known as clinical breakpoints) are used to categorize an organism as susceptible, susceptible-dose dependent, intermediate, resistant, or nonsusceptible according to breakpoint setting organizations, either the Clinical and Laboratory Standards Institute (CLSI) or the European Committee on Antimicrobial Susceptibility Testing (EUCAST), as applicable.

In some instances, an interpretive category cannot be provided based on available data; therefore, the following comment will be included on the report: There are no established interpretive guidelines for agents reported without interpretations.

For information regarding CLSI and EUCAST susceptibility interpretations, see Susceptibility Interpretative Category Definitions.

A positive result provides definitive evidence of the presence of Helicobacter pylori.

Organisms may be detected in asymptomatic (colonized) individuals.

False-negative culture results may occur since the organism may die between biopsy collection and laboratory culture.

Culture-negative results may occur due to the fastidious nature of the organism. Delays in specimen transportation will decrease recovery of the organism. Culture should be set up as soon as possible following specimen collection. Antimicrobial therapy may render the culture negative.

Due to Helicobacter pylori's fastidious nature and slow growth, it may take 7 days to recover the organism and up to an additional 21 days to perform antimicrobial susceptibility testing.

When antimicrobial susceptibilities are performed, in vitro susceptibility does not guarantee clinical response. Therefore, the decision to treat with a particular agent should not be based solely on the antimicrobial susceptibility, testing result. The Clinical and Laboratory Standards Institute has defined interpretive categories for clarithromycin. The antimicrobials for which the European Committee on Antimicrobial Susceptibility Testing has defined interpretive categories include amoxicillin, clarithromycin, levofloxacin, metronidazole rifampin, and tetracycline.

Chen D, Cunningham SA, Cole NC, Kohner PC, Mandrekar JN, Patel R: Phenotypic and molecular antimicrobial susceptibility of Helicobacter pylori. Antimicrob Agents Chemother. 2017;61(4):e02530-16

The selective Helicobacter pylori media used for isolation has a Brucella agar base with added vancomycin, trimethoprim, polymyxin B, and vitamin K1. Fresh medium and high humidity are essential for organism recovery. Plates are incubated at 35 degrees C in a microaerophilic atmosphere.(Couturier MR: Helicobacter. In: Carroll KC, Pfaller MA, eds. Manual of Clinical Microbiology. 12th ed. ASM Press; 2019:1044-1057)

The agar dilution method is used for susceptibility testing. The antimicrobial is added to agar in various concentrations depending upon levels attainable in serum. A standardized suspension of the organism is applied to the agar plates that are incubated for 72 hours at 35 degrees C. Complete inhibition of all but 1 colony or a very fine residual haze represents the endpoint.(Clinical and Laboratory Standards Institute [CLSI]. Methods for Antimicrobial Dilution and Disk Susceptibility Testing of Infrequently Isolated or Fastidious Bacteria. 3rd ed. CLSI document M45.CLSI; 2015)

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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.

87081-Helicobacter pylori culture

87077-Bacteria identification (if appropriate)

87153-Aerobe Ident by Sequencing (if appropriate)

87176-Tissue processing (if appropriate)

87181-Susceptibility per drug and per organism for drugs not in routine battery (if appropriate)

87186-Antimicrobial Susceptibility, Aerobic Bacteria, MIC-per organism for routine battery (if appropriate)

87150-H pylori + Clarithro Resistance PCR (if appropriate)