Gastrointestinal Pathogen Panel (GPP) PCR utilizing Luminex® xTAG®
The xTAG® Gastrointestinal Pathogen Panel (GPP) is a multiplexed nucleic acid test intended for the simultaneous qualitative detection and identification of multiple viral, parasitic, and bacterial nucleic acids in human stool specimens from individuals with signs and symptoms of infectious colitis or gastroenteritis.
The detection and identification of specific gastrointestinal microbial nucleic acid from individuals exhibiting signs and symptoms of gastrointestinal infection aids in the diagnosis of gastrointestinal infection when used in conjunction with clinical evaluation, laboratory findings, and epidemiological information. A gastrointestinal microorganism multiplex nucleic acid-based assay also aids in the detection and identification of acute gastroenteritis in the context of outbreaks. xTAG GPP positive results are presumptive and must be confirmed by FDA-cleared tests or other acceptable reference methods.¹
About Gastrointestinal Infections
Gastrointestinal infections in both pediatric and adult patients account for significant morbidity and mortality worldwide.2 In addition, immunocompromised hosts, including HIV patients, solid-organ transplant recipients or patients requiring therapy for chronic inflammatory diseases are susceptible to gastrointestinal infections.3 Mild diarrhea can lead to absenteeism from school or work and may require treatment by a health care provider. Patients with severe diarrhea may be hospitalized and some may develop more serious sequelae such as Guillain-Barré syndrome and hemolytic uremic syndrome (HUS), and in some cases death.4 Nearly three percent of neonatal mortality and 17 percent of under-five child mortality is attributable to diarrhea.5 Diarrheal disease can be caused by a number of pathogens including viruses, bacteria, and parasites. Presentations of gastroenteritis with an unidentified source pose a challenge to health care providers, as the same clinical presentation can be caused by different etiologies. Knowing the identity of the causal agent in symptomatic (both acute and chronic gastroenteritis) adult and pediatric patients can aid in diagnosis and patient management.1
Detects 11 Gastrointestinal Pathogen targets: Campylobacter (C. jejuni, C. coli and C. lari only), Clostridium difficile toxin A/B, Cryptosporidium (C. parvum and C. hominis only), Escherichia coli O157, Enterotoxigenic Escherichia coli (ETEC) LT/ST, Giardia (G. lamblia only, also known as G. intestinalis and G. duodenalis), Norovirus GI/GII, Rotavirus A, Salmonella, Shiga Toxin-producing Escherichia coli (STEC) stx1/stx2, and Shigella (S. boydii, S. sonnei, S. flexneri and S. dysenteriae).
Same day (within 12-18 hours from receipt of specimen), Monday through Saturday.
|Specimen Type||Order Code||CPT Code||NY Approved||Volume||Assay Range||Special Instructions|
Size of pea, or 2 mL liquid stool
Positive/Not Detected For Assay Limitations see below
Qualitative (Positive, Not Detected) for: Campylobacter, Clostridium difficile toxin A/B, Cryptosporidium, Escherichia coli O157, Enterotoxigenic Escherichia coli (ETEC), Giardia lamblia (also known as G. intestinalis and G. duodenalis), Norovirus GI/GII, Rotavirus A, Salmonella, Shiga Toxin-producing Escherichia coli (STEC), and Shigella.
1. Positive results obtained using the xTAG GPP assay are presumptive and must be confirmed with an FDA cleared or approved test or other acceptable reference method. All results should be used and interpreted in the context of a full clinical evaluation as an aid in the diagnosis of gastrointestinal infection.
a. There is a risk of false positive values resulting from cross-contamination by target organisms, their nucleic acids or amplified product.
b. There is a risk of false positive values resulting from non-specific signals in the assay.
2. Analyte targets (virus, bacteria or parasite nucleic acid sequences) may persist in vivo, independent of virus, bacteria or parasite viability. Detection of analyte target(s) does not guarantee that the corresponding live organism(s) is present, or that the corresponding organism(s) is the causative agent for clinical symptoms.
3. As with any hybridization-based assay, underlying polymorphisms in primer-binding regions can affect the targets being detected and subsequently the calls made.
4. Campylobacter: the xTAG GPP assay was designed to detect C. jejuni, C. coli and C. lari; however, some strains of Campylobacter fetus subsp. fetus may be detected, (Campylobacter fetus subsp. fetus (NCTC 10842, type strain [ATCC 27374]) at a concentration of 6 x108 cfu/mL resulted in a positive call for Campylobacter).
5. Escherichia coli (Migula) Castellani and Chalmers strain CDC EDL 1284 [929-78] (serotype O124:NM [ATCC 43893]) (enteroinvasive) resulted in a positive call for Shigella.
6. Cryptosporidium: the xTAG GPP assay detects C. parvum and C. hominis only.
7. Giardia: xTAG GPP assay detects G. lamblia only (also known as G. intestinalis and G. duodenalis).
8. Primers for Shigella are expected to cross-react with enteroinvasive E. coli (EIEC) and Salmonella subterranean (at a concentration of 6 x 108 cfu/mL). Enteroinvasive E. coli (strain CDC EDL 1284 [929-78], serotype O124:NM) cross-reacting with Shigella in the xTAG GPP kit is expected as EIEC is genetically, biochemically and physiologically closely related to Shigella. EIEC strains possess some of the biochemical characteristics of E. coli, but some strains can cause dysentery using the same method of invasion used by Shigella. Both Shigella and EIEC can be separated from other E. coli by PCR targeting the invasion plasmid antigen H (ipaH) gene. However, PCR alone cannot distinguish between Shigella from EIEC. Additional physiological and biochemical typing, and serological typing must be used in combination with the ipaH gene PCR to distinguish between Shigella and EIEC. EIEC also causes diarrhea predominantly in tropical countries with occasional cases reported in the US.
9. There is a risk of false negative values due to the presence of strain/species sequence variability in the targets of the assay, procedural errors, amplification inhibitors in specimens, or inadequate numbers of organisms for amplification.
10. A target call of STEC stx1/stx2 may be from either Shigella dysenteriae or from STEC.
11. The performance of this test has not been established for monitoring treatment of infection with any of the panel organisms.
12. Positive and negative predictive values are highly dependent on prevalence. False negative test results are more likely prevalent when disease is high. False positive test results are more likely during periods when prevalence is low.
13. This test is a qualitative test and does not provide the quantitative value of detected organism present.
Specimens beyond their acceptable length of time from collection as listed in the specimen handling, or specimen types other than those listed.
Specimens are approved for testing in New York only when indicated in the Specimen Information field above.
The CPT codes provided are based on Viracor Eurofins' interpretation of the American Medical Association's Current Procedural Terminology (CPT) codes and are provided for informational purposes only. CPT coding is the sole responsibility of the billing party. Questions regarding coding should be addressed to your local Medicare carrier. Viracor Eurofins assumes no responsibility for billing errors due to reliance on the CPT codes illustrated in this material.
Information derived from Gastrointestinal Pathogen Panel Package Insert (Luminex Corporation). Gastrointestinal Pathogen Panel is a product of Luminex Corporation. xTAG is a registered trademark of Luminex Corporation. Luminex is a registered trademark of Luminex Corporation.
1 Information derived from the xTAG Gastrointestinal Pathogen Panel test kit package insert (Luminex, Inc.).
2 Schlenker C, Surawicz CM. Emerging infections of the gastrointestinal tract. Best Pract Res Clin Gastroenterol. 2009;23(1);89-99.
3 Thom K, Forrest G. Gastrointestinal infections in immunocompromised hosts. Curr Opin Gastroenterol. 2006 Jan;22(1):18-23.
4 Fischer Walker CL, Sack D, Black RE. Etiology of diarrhea in older children, adolescents and adults: a systematic review. PLoS Negl Trop Dis. 2010 Aug 3;4(8);e768.
5 Patel A, Mamtani M, Dibley MJ, Badhoniya N, Kulkarni H. Therapeutic value of zinc supplementation in acute and persistent diarrhea: a systematic review. PLoS One. 2010 Apr 28;5(4):e10386.