N-acetyl-D-glucosamine for enhanced specificity of strep a immunoassay
Methods, compositions and kits for detecting Group A Streptococcus in a biological sample are described. More particularly, the present disclosure provides an immunoassay in which the specificity of detection of Group A Streptococcus is enhanced by addition of N-acetyl-D-glucosamine. These methods, compositions and kits are useful in convenient, reliable and early diagnosis of streptococcal infection in a human subject.
1. A kit, comprising:
a device comprising:
a matrix comprising (i) a sample receiving zone, (ii) a labeling zone containing a labeled antibody with specific binding to Group A Streptococcus antigen, to form a labeled antibody-bound antigen, and (iii) a capture zone having means for specifically binding the antibody-bound antigen thereon, wherein the sample receiving zone, the labeling zone and the capture zone are arranged on the matrix in a liquid flow path; and
a container comprising an extraction reagent;
wherein at least one of the sample receiving zone, the labeling zone, or the extraction reagent, comprises N-acetyl-D-glucosamine (NAG) monomer.
2. The kit of claim 1 , wherein the extraction reagent comprises NAG monomer.
3. The kit of claim 2 , wherein the container comprising the extraction reagent is configured to receive a biological sample to provide a treated sample.
4. The kit of claim 3 , further comprising a dropper tip configured to fit securely on the container comprising the extraction reagent after the container receives the biological sample.
5. The kit of claim 1 , wherein the sample receiving zone comprises NAG monomer.
6. The kit of claim 1 , wherein the labeling zone comprises NAG monomer.
7. The kit of claim 1 , wherein the NAG monomer reduces the rate of false positives for providing accurate detection of Group A Streptococcus infection.
8. The kit of claim 1 , wherein the antibody is fluorescently labeled.
9. The kit of claim 1 , further comprising an instrument for collecting a biological sample.
10. The kit of claim 9 , wherein in instrument is a swab.
11. The kit of claim 1 , further comprising instructions for use.
12. The kit of claim 11 , wherein the instructions do not caution to not touch the tongue, sides or top of mouth with the instrument when collecting the biological sample.
13. The kit of claim 1 , further comprising reference samples.
14. The kit of claim 13 , wherein the reference sample is a positive control swab coated with heat-inactivated, non-infectious Group A Streptococcus.
15. The kit of claim 13 , wherein the reference sample is a negative control swab that was coated with heat-inactivated, non-infectious Group C Streptococcus.
16. The kit of claim 1 , wherein the device comprises a lateral flow immunoassay test strip housed in a cassette.
17. A method for detecting the presence or absence of Group A Streptococcus in a biological sample, comprising:
providing a kit according to claim 1 ;
placing a biological sample in the extraction reagent to form a treated sample;
placing the treated sample on the sample receiving zone of the device; and
determining the presence or absence of Group A Streptococcus.
18. The method of claim 17 , further comprising:
providing an instrument for collecting the biological sample; and
collecting a biological sample on the instrument.
19. The method of claim 17 , further comprising:
providing instructions for use, wherein the instructions do not caution to not touch the tongue, sides or top of mouth with the instrument when collecting the sample.