XPECT GIARDIA LATERAL FLOW ASSAY, MODEL 2450020

K031942 · Remel, Inc. · MHI · Nov 18, 2003 · Microbiology

Device Facts

• Record ID: K031942
• Device Name: XPECT GIARDIA LATERAL FLOW ASSAY, MODEL 2450020
• Applicant: Remel, Inc.
• Product Code: MHI · Microbiology
• Decision Date: Nov 18, 2003
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.3220
• Device Class: Class 2

Indications for Use

Xpect Giardia kit is an in vitro qualitative immunoassay for the detection of Giardia antigens in preserved and unpreserved fecal specimens. This test is intended as an aid in the laboratory diagnosis of suspected Giardia infections.

Device Story

Xpect™ Giardia Lateral Flow Assay is a chromatographic immunoassay for detecting Giardia antigen in fecal specimens. Input: fecal specimen (preserved or unpreserved) added to a dilution tube with buffered solution and conjugate containing colored micro-particles linked to murine monoclonal anti-Giardia antibody. Process: mixture dispensed into device sample well; wicks along membrane containing capture antibody stripes. If Giardia antigen is present, it forms an immune complex that binds to the test line (rabbit anti-Giardia antibody). Unbound particles are captured at the control line (anti-mouse antibody). Output: visual blue line at test position indicates positive result; control line indicates test validity. Used in laboratory settings by trained personnel. Results aid clinicians in diagnosing Giardia infections, facilitating timely patient management.

Clinical Evidence

Performance evaluated at six geographically diverse laboratories. Compared to microscopy (n=575), sensitivity was 97.9% (95/97; 95% CI: 92.8-99.4%) and specificity was 97.1% (464/478; 95% CI: 95.1-98.2%). Compared to the predicate device (n=147), percent agreement was 93.9% (138/147). Reproducibility testing across seven sites with 630 samples showed 100% agreement with expected results. No cross-reactivity observed with 28 common enteric organisms. No interference from blood, mucin, fecal fat, or common anti-diarrheal medications.

Technological Characteristics

Qualitative immunochromatographic lateral flow assay. Components: Mylar-backed nitrocellulose membrane, rabbit anti-Giardia capture antibodies, goat anti-mouse IgG control line, and blue polystyrene microparticles coated with anti-Giardia monoclonal antibodies. Sample volume: 100μl. Detection limit: 1 organism per 0.1 ml. Standalone manual test format.

Indications for Use

Indicated for the qualitative detection of Giardia antigens in preserved and unpreserved human fecal specimens to aid in the laboratory diagnosis of suspected Giardia infections in patients of all ages.

Regulatory Classification

Identification

Entamoeba histolytica serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies to Entamoeba histolytica in serum. Additionally, some of these reagents consist of antisera conjugated with a fluorescent dye (immunofluorescent reagents) used to identify Entamoeba histolytica directly from clinical specimens. The identification aids in the diagnosis of amebiasis caused by the microscopic protozoan parasite Entamoeba histolytica and provides epidemiological information on diseases caused by this parasite. The parasite may invade the skin, liver, intestines, lungs, and diaphragm, causing disease conditions such as indolent ulcers, an amebic hepatitis, amebic dysentery, and pulmonary lesions.

Special Controls

*Classification.* Class II (special controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to § 866.9.

Predicate Devices

• Becton Dickinson ColorPAC™ Giardia/Cryptosporidium Rapid Assay (K983399)

Submission Summary (Full Text)

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510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION
DECISION SUMMARY
DEVICE ONLY TEMPLATE

A. 510(k) Number:
K031942

B. Analyte:
Giardia antigens

C. Type of Test:
Chromatographic immunoassay

D. Applicant:
Remel Inc.

E. Proprietary and Established Names:
Xpect™ Giardia Lateral Flow Assay

F. Regulatory Information:
1. Regulation section:
21 CFR Part 866.3220 Entamoeba histolytica serological reagents
2. Classification:
Class II
3. Product Code:
MHI – Giardia spp.
4. Panel:
83 (Microbiology)

G. Intended Use:
1. Intended use(s):
Xpect Giardia kit is an in vitro qualitative immunoassay for the detection of Giardia antigens in preserved and unpreserved fecal specimens. This test is intended as an aid in the laboratory diagnosis of suspected Giardia infections.
2. Indication(s) for use:
Xpect Giardia kit is an in vitro qualitative immunoassay for the detection of Giardia antigens in preserved and unpreserved fecal specimens. This test is intended as an aid in the laboratory diagnosis of suspected Giardia infections
3. Special condition for use statement(s):
Not applicable
4. Special instrument Requirements:
Not applicable

H. Device Description:
The kit contains 20 test devices consisting of a membrane striped with rabbit anti-Giardia, and goat anti-mouse IgG; conjugate consisting of dark-blue microparticles coated with anti-Giardia MAb, and dark blue microparticles coated with mouse IgG; specimen dilution buffer; a procedure card; disposable transfer pipettes, dilution tubes and instructions for use.

I. Substantial Equivalence Information:
1. Predicate device name(s):

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BD ColorPAC Giardia/Crypto Rapid Assay

2. Predicate K number(s):
K 983399

3. Comparison with predicate:

| Similarities | | |
| --- | --- | --- |
| Item | Device | Predicate |
| Intended Use | Detection of Giardia antigens in fecal specimens | Detection of Giardia and Cryptosporidium antigens in fecal specimens |
| Technology | Qualitative immunochromatographic assay | Qualitative immunochromatographic assay |
| Antibodies:conjugate | Monoclonal anti-Giardia and normal mouse IgG | Rabbit anti-Giardia, monoclonal anti-Giardia and Cryptosporidium |
| Specimen type | Human stool preserved in 10% formalin, SAF or Cary Blair | Human stool preserved in 10% formalin, SAF, MIF, or Cary Blair |
| Differences | | |
| Item | Device | Predicate |
| Capture antibodies or molecules | Rabbit anti-Giardia and goat anti-mouse IgG | Mouse anti-Cryptosporidium, goat anti-mouse IgG, avidin derivative |
| Material: membrane | Mylar-backed nitrocellulose | Nitrocellulose |
| Material: conjugate | Anti-Giardia and mouse IgG colored polystyrene particles diluted in buffer | Colloidal dye labeled monoclonal antibodies to Giardia and Cryptosporidium |
| Sample volume | 100μl | 50μl |

J. Standard/Guidance Document Referenced (if applicable):
Not applicable

K. Test Principle:
The Xpect™ Giardia Lateral Flow Assay is a chromatographic immunoassay that detects the presence of Giardia antigens. The test utilizes sample wicking to capture Giardia antigens on discrete test lines containing antigen-specific antibodies for each organism. A specimen is added to a dilution tube containing a buffered solution. A conjugate containing colored micro-particles linked to murine monoclonal antibody specific for Giardia is added. The mixture is dispensed into the sample well of the device and wicks across a membrane containing capture antibody strips. The Giardia immune complex is present, reacts with anti-Giardia antibody at the test line. Conjugates not bound at the test

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lines are later captured at the control line containing anti-mouse antibody. A blue line will appear at the Giardia test position if Giardia antigen is present. A line in the Control position indicates that the test is working properly.

L. Performance Characteristics (if/when applicable):

1. Analytical performance:

a. Precision/Reproducibility:
Reproducibility testing was conducted at seven sites, including one in-house site, on three separate days with ten blinded samples of varying activity. All samples tested for Giardia produced the expected result.

b. Linearity/assay reportable range:
Not applicable

c. Traceability (controls, calibrators, or method):
Not applicable

d. Detection limit:
For Giardia, detection limit was 1 organism per 0.1 ml. of specimen

e. Analytical specificity:

Cross-reactivity:
No cross-reactivity was observed using samples containing the following organisms: Ascaris lumbricoides, Blastocystis hominis, Campylobacter coli, Campylobacter jejuni, Candida albicans, Chilomastix mesnili, Cryptosporidium parvum, Cyclospora cayetanensis, Dientamoeba fragilis, Endolimax nana, Entamoeba coli, Entamoeba hartmanni, Entamoeba histolytica, Enterobius vermicularis, Escherichia coli, hookworm, Hymenolepis nana, Iodamoeba butschlii, Isospora sp., Microsporidia, Rotavirus, Salmonella choleraesuis subsp. choleraesuis serotype Typhimurium, Shigella dysenteriae, Shigella flexneri, Shigella sonnei, Strongyloides stercoralis, Taenia sp., and Trichuris trichiura. Cross-reactivity to Astrovirus and Caliciviruses has not been established.

Interfering Substances:

Prior to testing, positive and negative samples were spiked (20% v/v) with blood, mucin, fecal fat or the following over-the-counter anti-diarrheal products: Pepto-Bismol®, Imodium® A-D, and Kaopectate® (active ingredients: bismuth subsalicylate, loperamide HCl, and attapugite respectively). Testing indicated that none of these substances interfered with the expected result.

f. Assay cut-off:

The assay can detect 1 Giardia organism per 0.1 ml of specimen. Clinically relevant detection limits were determined using true clinical specimens diluted to an end point titration with the Xpect Giardia test. Sequential serial dilutions were tested until an endpoint dilution was reached. The endpoint dilution was defined as one dilution above where the sample became negative. The quantity of organisms detected at the titration endpoint in each specimen was calculated from the numbers seen microscopically in a 10 μl sample using DFA.

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2. Comparison studies:

a. Method comparison with predicate device:

Percent Agreement:

The Xpect™ Giardia was compared to a commercially available lateral flow test - the predicate device. The Percent Agreement of the Xpect™ Giardia assay versus the predicate device was as follows:

| Giardia | Predicate Device | | | |
| --- | --- | --- | --- | --- |
| | | + | | - |
| Xpect™ | + | 24 | | 7 |
| | - | 2 | 114 | Agreement |
| Total | | 26 | 121 | 93.9% (138/147) |

b. Matrix comparison:

Not applicable

3. Clinical studies:

a. Clinical sensitivity:

Sensitivity/Specificity:

The performance of the Xpect™ Giardia was evaluated at six geographically diverse laboratories. The overall sensitivity and specificity of the test were compared to microscopy. Performance relative to patients' clinical status has not been established. The overall sensitivity and specificity for Giardia are listed below.

| Giardia | Microscopy | | |
| --- | --- | --- | --- |
| | | + | - |
| Xpect™ | + | 95 | 14 |
| | - | 2 | 464 |
| | Total | 97 | 478 |

Sensitivity: 97.9% (95/97); 95% CI = 92.8-99.4%

Specificity: 97.1% (464/478); 95% CI = 95.1-98.2%

Note: CI = Confidence Interval

b. Clinical specificity:

Refer to (a) above

c. Other clinical supportive data (when a and b are not applicable):

Not applicable

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4. Clinical cut-off:
See assay cut off above

5. Expected values/Reference range:
Expected values were established from literature. Worldwide, Giardia is the most commonly identified parasite in stool specimens with a prevalence rate of 2-5%. Incidence of giardiasis is higher in children than in adults. In the USA, the asymptomatic carriage rate of Giardia is estimated to be 3-7%. Rates tend to be higher in southern USA regions and in children younger than 36 months who attend daycare centers.

M. Conclusion:
In clinical settings, the Xpect™ Giardia Lateral Flow Assay is substantially equivalent in performance to the predicate device and to microscopic examination for the identification of Giardia in fecal specimens.