Test Id : STRNG
Strongyloides Antibody, IgG, Serum
Useful For
Suggests clinical disorders or settings where the test may be helpful
Screening for the presence of IgG-class antibodies to Strongyloides
This test is not useful for monitoring patient response to therapy as IgG-class antibodies to Strongyloides may remain detectable following resolution of infection.
Highlights
This assay detects IgG-class antibodies only.
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
For more information see Parasitic Investigation of Stool Specimens Algorithm.
Method Name
A short description of the method used to perform the test
Enzyme-Linked Immunosorbent Assay (ELISA)
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
Aliases
Lists additional common names for a test, as an aid in searching
Strongyloidiasis
Strongyloides antibody
Strongyloides Hyperinfection
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
For more information see Parasitic Investigation of Stool Specimens Algorithm.
Specimen Type
Describes the specimen type validated for testing
Serum
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Special Instructions
Library of PDFs including pertinent information and forms related to the test
Forms
If not ordering electronically, complete, print, and send Infectious Disease Serology Test Request (T916) with the specimen.
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
0.4 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
| Heat inactivated specimen | 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 |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 30 days | |
| Frozen | 30 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
Screening for the presence of IgG-class antibodies to Strongyloides
This test is not useful for monitoring patient response to therapy as IgG-class antibodies to Strongyloides may remain detectable following resolution of infection.
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
For more information see Parasitic Investigation of Stool Specimens Algorithm.
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Strongyloidiasis is caused by Strongyloides stercoralis, a nematode endemic to tropical and subtropical regions worldwide. S stercoralis is also prominent in the Southeastern US, including in rural areas of Kentucky, Tennessee, Virginia, and North Carolina. A small series of epidemiological studies in the US identified that 0% to 6.1% of individuals sampled had antibodies to S stercoralis.
S stercoralis has a complex lifecycle that begins with maturation to the infective filariform larva in warm, moist soil. The larvae subsequently penetrate exposed skin and migrate hematogenously to the lungs, from where they ascend the bronchial tree and are swallowed. Once in the small intestine, filariform larva matures into the adult worms that burrow into the mucosa. Gravid female worms produce eggs that develop into noninfectious rhabditiform larvae in the gastrointestinal tract and are eventually released in the stool. The time from dermal penetration to appearance of Strongyloides in stool samples is approximately 3 to 4 weeks.
The most common manifestations of infection are mild and may include epigastric pain, mild diarrhea, nausea, and vomiting. At the site of filariform penetration, skin may be inflamed and itchy-this is referred to as "ground itch." Migration of the larva through the lungs and up the trachea can produce a dry cough, wheezing, and mild hemoptysis. Eosinophilia, though common among patients with strongyloidiasis, is not a universal finding, and the absence of eosinophilia cannot be used to rule-out infection.
In some patients, particularly those with a depressed immune system, the rhabditiform larvae may mature into the infectious filariform larvae in the gastrointestinal tract and lead to autoinfection. The filariform larvae subsequently penetrate the gastrointestinal mucosa, migrate to the lungs, and can complete their lifecycle. Low-level autoinfection can maintain the nematode in the host for years to decades. Among patients who become severely immunocompromised, however, autoinfection may lead to hyperinfection and fatal disseminated disease. Hyperinfection has also been associated with underlying human T-cell lymphotropic virus type 1 (HTLV-1) infection. Uncontrolled, the larvae can disseminate to the lungs, heart, liver, and central nervous system. Septicemia and meningitis are common in cases of Strongyloides hyperinfection due to seeding of the bloodstream and central nervous system with bacteria originating from the gastrointestinal tract.
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
Reference values apply to all ages.
Interpretation
Provides information to assist in interpretation of the test results
Positive:
IgG antibodies to Strongyloides were detected, suggesting current or past infection. False-positive results may occur with other helminth infections (eg, Trichinella, Taenia solium). Clinical correlation is required.
Negative:
No detectable levels of IgG antibodies to Strongyloides. Repeat testing in 10 to 14 days if clinically indicated.
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
False-positive results may occur with other helminth infections, including prior exposure to Entamoeba histolytica, Ascaris, Taenia solium, Fasciola species, Echinococcus species, Schistosoma species, and Toxocara (per assay manufacturer).
This assay should not be used alone to establish a diagnosis of strongyloidiasis. Results should be correlated with other laboratory findings and through clinical evaluation.
False-negative results may occur during acute or localized infection. A single negative result should not be used to rule-out infection.
The seroprevalence of IgG-class antibodies to Strongyloides stercoralis ranges from 0% to 6.1% in the United States.
Supportive Data
Accuracy:
The Bordier Strongyloides enzyme immunoassay was compared to the Strongyloides luciferase immunoprecipitation (LIPS) assay as performed at the National Institutes of Health and to the SciMedix Strongyloides IgG enzyme-linked immunosorbent assay using 102 serum samples. Based on prior publications, the LIPS assay was considered the gold standard comparator for this evaluation.(1,2) The comparative data is shown below in Tables 1, 2, and 3:
Table 1. Comparison of results between the Bordier and NIH LIPS assays (n=102)
| | NIH LIPS | ||
| Positive | Negative | ||
| Bordier | Positive | 51 | 12 |
| Negative | 3 | 36 | |
Positive Agreement: 96.2% (51/53); 95% CI: 86.5%-99.7%
Negative Agreement: 75.0% (36/48); 95% CI: 61.1%-85.2%
Overall Agreement: 85.3% (87/102); 95% CI: 77.0%-91.0%
Table 2. Comparison of results between the Bordier and SciMedx assays (n=102)
| SciMedx | ||||
| Positive | Negative | Equivocal | ||
| Bordier | Positive | 45 | 13 | 5 |
| Negative | 8 | 30 | 1 | |
Positive Agreement: 84.9% (45/53); 95% CI: 72.7%-92.4%
Negative Agreement: 69.8% (30/43); 95% CI: 54.8%-81.5%
Overall Agreement: 73.5% (75/102); 95% CI: 64.2%-81.2%
Table 3. Comparison of results between the SciMedx and NIH LIPS assays (n=102)
| NIH LIPS | |||
| Positive | Negative | ||
| SciMedix | Positive | 42 | 11 |
| Negative | 7 | 36 | |
| Equivocal* | 5 | 1 | |
*Equivocal results were excluded from calculation of positive and negative agreement.
Positive Agreement: 85.7% (42/49); 95% CI: 73.0%-93.2%
Negative Agreement: 76.6% (36/47); 95% CI: 62.6%-86.6%
Overall Agreement: 76.5% (78/102); 95% CI: 67.3%-83.7%
Reference Range:
Evaluation was performed on 100 normal donor serum samples by the Bordier Strongyloides assay and 99% (99/100) were negative.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Ramanathan R, Burbelo PD, Groot S, Iadarola MJ, Neva FA, Nutman TB. A luciferase immunoprecipitation systems assay enhances the sensitivity and specificity of diagnosis of Strongyloides stercoralis infection. J Infect Dis. 2008;198(3):444-451
2. Starr MC, Montgomery SP. Soil-transmitted Helminthiasis in the United States: a systematic review-1940-2010. Am J Trop Med Hyg. 2011;85(4):680-684
3. Krolewiecki AJ, Ramanathan R, Fink V, et al. Improved diagnosis of Strongyloides stercoralis using recombinant antigen-based serologies in a community-wide study in northern Argentina. Clin Vaccine Immunol. 2010;17(10):1624-1630
4. Centers for Disease Control and Prevention. Global Health. Division of Parasitic Diseases and Malaria: Parasites-Strongyloides: Epidemiology and Risk Factors. CDC; Updated February 16, 2024. Accessed December 9, 2024. Available at www.cdc.gov/parasites/strongyloides/epi.html
Method Description
Describes how the test is performed and provides a method-specific reference
The Bordier Strongyloides ratti IgG enzyme-linked immunosorbent assay is an enzymatically amplified sandwich-type immunoassay. After a blocking step, diluted serum and controls are incubated in antigen-coated microtiter wells, then washed and incubated with antihuman-IgG antibody labeled with protein A-alkaline phosphatase conjugate. After a washing step, the wells are incubated with phosphatase substrate. The reaction is halted by potassium phosphate stopping solution and the degree of enzymatic turnover is determined by absorbance measured at 405 nanometers with a reference filter of 590 to 650 nm.(Package insert: Strongyloides Ratti Enzyme immunoassay for the diagnosis of human Strongyloidosis. Bordier Affinity Products SA; 01/2023)
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, Wednesday, Thursday, Friday
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.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Fees :
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.
CPT codes are provided by the performing laboratory.
86682
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 |
|---|---|---|
| STRNG | Strongyloides Ab, IgG, S | 34376-4 |
| 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.
|
|---|---|---|
| STRNG | Strongyloides Ab, IgG, S | 80660-4 |