Accu-Tell® Typhoid Rapid Test Cassette (Whole Blood/Serum/Plasma)

Accu-Tell® Typhoid Rapid Test Cassette (Whole Blood/Serum/Plasma) is a rapid chromatographic immunoassay for the simultaneous detection and differentiation of IgG and IgM types of antibodies against Salmonella typhi (S. typhi) in human whole blood, serum or plasma. It is intended to be used as a screening test as an aid in the diagnosis of infection with S. typhi.

Product Description

CATALOG

KEY POINTS

Detection for: IgG and IgM antibodies to Salmonella typhi (S. typhi) in human whole blood, serum or plasma

Specimen volume: Serum or Plasma Specimen: 40μL

                                 Venipuncture or Fingerstick Whole Blood Specimen: 40μL

Reading time: 15 minutes

IgG Results:

Sensitivity: 89.5% (95%CI: 66.9%~98.7%)

Specificity: 97.2% (95%CI: 93.9%~98.9%)

Accuracy: 96.5% (95%CI: 93.3%~98.5%)

IgM Results

Sensitivity: 87.9% (95%CI: 71.8%~96.6%)

Specificity: 97.4% (95%CI: 94.5%~99.1%)

Accuracy: 96.3% (95%CI: 93.2%~98.2%)

INTRODUCTION

Typhoid fever is caused by S. typhi, a Gram-negative bacterium. World-wide an estimated 17 million cases and 600,000 associated deaths occur annually1. Patients who are infected with HIV are at significantly increased risk of clinical infection with S. typhi2. Evidence of h. pylori infection also presents an increase risk of acquiring typhoid fever. 1-5% of patients become chronic carrier harboring S. typhi in the gallbladder.

INTENDED USE

ACCU-TELL® Typhoid Rapid Test Cassette (Whole Blood/Serum/Plasma) is a rapid chromatographic immunoassay for the simultaneous detection and differentiation of IgG and IgM types of antibodies against Salmonella typhi (S. typhi) in human whole blood, serum or plasma. It is intended to be used as a screening test as an aid in the diagnosis of infection with S. typhi. Any reactive specimen with ACCU-TELL® Typhoid Rapid Test Cassette (Whole Blood/Serum/Plasma) needs to be confirmed with alternative testing method.

1. Bring the pouch to room temperature before opening it. Remove the test cassette from the sealed pouch and use it within one hour. Best results will be obtained if the assay is performed within one hour.

2. Place the test cassette on a clean and level surface.

For Serum or Plasma specimen:

3. Hold the dropper vertically and transfer 1 drop of serum or plasma (approximately 40μL) to the specimen well of test Cassette， then add 1 drop of buffer (approximately 40μL) and start the timer. Avoid trapping air bubbles in the specimen well. See the illustration above.

For Venipuncture Whole Blood specimen:

3. Hold the dropper vertically and transfer 1 drop of whole blood (approximately 40 μL)to the specimen well, then add 2 drops of buffer (approximately 80μL), and start the timer. See illustration above.

For Finger stick Whole Blood specimen:

3. To use a capillary tube: Fill the capillary tube and transfer approximately 40μL of finger stick whole blood specimen to the specimen area of test cassette, then add 2 drops of buffer (approximately 80μL) and start the timer. See illustration above.

4. Wait for the colored line(s) to appear. The result should be read at 15 minutes. Do not interpret results after 15minutes.

PERFORMANCE CHARACTERISTICS

Sensitivity and Specificity

A clinical evaluation was conducted comparing the results obtained using ACCU-TELL® Typhoid Rapid Test Cassette (Whole Blood/Serum/Plasma) to Typhoid IgG/IgM ELISA Testing. The study included 231 IgG specimens and 268 IgM specimen, and about the IgG specimen both assays identified 206 negative and 17 positive results, about the IgM specimen both assays identified 229 negative and 29 positive results.

IgG Results

Sensitivity: 89.5% (95%CI: 66.9%~98.7%)

Specificity: 97.2% (95%CI: 93.9%~98.9%)

Accuracy: 96.5% (95%CI: 93.3%~98.5%)

CI: Confidence Interval

IgM Results

Sensitivity: 87.9% (95%CI: 71.8%~96.6%)

Specificity: 97.4% (95%CI: 94.5%~99.1%)

Accuracy: 96.3% (95%CI: 93.2%~98.2%)

CI: Confidence Interval

Precision

Intra-Assay

Within-run precision has been determined by using 10 replicates of three specimens: a negative, a low positive, and a high positive. The negative, low positive, and high positive values were correctly identified >99% of the time.

Inter-Assay

Between-run precision has been determined by 10 independent assays on the same three specimens: a negative, a low positive, and a high positive. Three different lots of ACCU-TELL® Typhoid Rapid Test Cassette (Whole Blood/Serum/Plasma) have been tested over a 3-day period using negative, low positive, and high positive specimens. The specimens were correctly identified >99% of the time.

Cross-reactivity

ACCU-TELL® Typhoid Rapid Test Cassette (Whole Blood/Serum/Plasma) has been tested for HBsAg, HBsAb, HbeAg, HBeAb, HBcAb, HCV,HIV, Syphilis, H. Pylori, CMV, Rubella and Toxo positive specimens. The results showed no cross-reactivity.

Interfering Substances

The following potentially interfering substances were added to Typhoid negative and positive specimens.

Acetaminophen:       20 mg/Dl                Caffeine:        20 mg/dL

Acetylsalicylic Acid:  20 mg/dL               Gentisic Acid: 20 mg/dL

Ascorbic Acid:          2g/dL                      Albumin:         2 g/dL

Bilirubin:                  1g/dL                       Oxalic Acid:    600mg/dL

None of the substances at the concentration tested interfered in the assay.

LIMITATIONS

1. The assay procedure and the test result interpretation must be followed closely when performing the assay. Failure to follow the procedure may give inaccurate results.

2. ACCU-TELL® Typhoid Rapid Test Cassette (Whole Blood/Serum/Plasma) is for qualitative detection of antibodies to S. typhi in human whole blood, serum or plasma. The intensity of the test band has not linear correlation with the antibody titer in the specimen.

3. A negative result only indicates absence of anti-S. typhi antibodies above detectable levels. A negative test result does not preclude the possibility of exposure to S. typhi as a negative result can occur if the quantity of anti-S typhi antibodies present in the specimen is below the detection limit of the assay, or the antibodies that are detected are not present during the stage of disease in which a sample is collected.

4. Specimens containing unusually high titer of heterophile antibodies or rheumatoid factor may affect expected results.

5. The results obtained with this test should only be interpreted in conjunction with other diagnostic procedures and clinical findings.

Note: The above information is for reference use only. Please refer to the product insert.