Diagnostic system
Methods and systems are provided for point-of-care nucleic acid amplification and detection. One embodiment of the point-of-care molecular diagnostic system includes a cartridge and an instrument. The cartridge can accept a biological sample, such as a urine or blood sample. The cartridge, which can comprise one or more of a loading module, lysis module, purification module and amplification module, is inserted into the instrument which acts upon the cartridge to facilitate various sample processing steps that occur in order to perform a molecular diagnostic test.
1. A method of testing a sample suspected of containing one or more target pathogens, comprising:
accepting a cartridge having a sample port assembly containing the sample suspected of containing the one or more target pathogens;
advancing the sample suspected of containing the one or more target pathogens to a lysis chamber within the cartridge having at least one lysis reagent therein;
mixing the sample with the at least one lysis agent to generate a lysed sample;
passing the lysed sample through a first porous solid support within the cartridge to capture a nucleic acid on the porous solid support;
releasing the captured nucleic acid from the first porous solid support to generate an enriched nucleic acid;
introducing the enriched nucleic acid into a rehydration chamber within the cartridge containing one or more dried reagents;
after introducing the enriched nucleic acid into a metering channel, mixing the contents of the rehydration chamber to produce an analyte/reagent solution;
distributing the analyte/reagent solution to two or more assay chambers within the cartridge;
combining the analyte/reagent solution with one or more amplification reagents after performing the distributing step;
sealing each one of the two or more assay chambers within the cartridge containing analyte/reagent solution from each one of all the other two or more assay chambers within the cartridge containing analyte/reagent solution and a waste chamber; and
performing an isothermal amplification reaction within each one of the two or more assay chambers in the cartridge while simultaneously detecting amplification product, wherein presence of an amplification product is an indication of a presence, an absence or a quantity of the one or more target pathogens in the sample suspected of containing the one or more target pathogens.
2. The method of testing a sample according to claim 1 , wherein in mixing the sample with the at least one lysis agent, the lysis agent is a mechanical agent.
3. The method of testing a sample according to claim 2 , wherein the mechanical agent is ceramic beads, glass beads or steel beads, and the mixing the sample step comprises rotating a stir bar within the lysis chamber at at least 1000 rpm.
4. The method of testing a sample according to claim 3 , wherein mixing the sample comprises rotating the stir bar or the ceramic, glass or steel beads along with a chemical lysis agent.
5. The method of testing according to claim 1 , wherein the at least one lysis agent is a chemical lysis agent.
6. The method of testing a sample according to claim 5 , wherein the one or more target pathogens is a virus or a gram-negative bacterium and the lysis reagent is a chaotropic agent.
7. The method of testing a sample according to claim 1 , wherein prior to passing the lysed sample through the porous solid support, the method further comprises passing the lysed sample through a size-exclusion filter, wherein nucleic acid passes through the filter.
8. The method of testing a sample according to claim 1 , wherein reagents comprises a primer set specific to one of the one or more target pathogens.
9. The method of testing a sample according to claim 1 , wherein a first assay chamber contains a primer set specific to a first nucleic acid sequence.
10. The method of testing a sample according to claim 9 , wherein the first nucleic acid sequence is present in one of the one or more target pathogens.
11. The method of testing a sample according to claim 9 , wherein prior to mixing the sample with at least one lysis agent, a process control is added to the sample and the first nucleic acid sequence is present in the process control.
12. The method of testing a sample according to claim 9 , wherein prior to passing lysed sample through the porous solid support, a process control is added to the lysed sample and the first nucleic acid sequence is present in the process control.
13. The method of testing a sample according to claim 9 , wherein a second assay chamber contains a primer set specific to a second nucleic acid sequence, wherein the second nucleic acid sequence is present in one of the one or more target pathogens.
14. The method of testing a sample according to claim 1 , wherein the performing an isothermal amplification reaction step is completed in less than 15 minutes.
15. The method of testing a sample according to claim 1 , further comprising: providing a result containing a determination made during the performing step relating to the presence, the absence or the quantity of the one or more target pathogens in the sample suspected of containing the one or more target pathogens.
16. The method of testing a sample according to claim 1 , wherein the method further comprises, prior to advancing the sample to a lysis chamber, pretreating the sample with a chemical reaction.
17. The method of testing a sample according to claim 16 , wherein the sample is sputum and the chemical reaction is incubation with a mucolytic agent.
18. The method of testing a sample according to claim 1 , wherein the method further comprises, prior to advancing the sample to a lysis chamber, pretreating the sample with an enzymatic reaction.
19. The method of testing a sample according to claim 18 , wherein the enzymatic reaction is incubation of the sample with a nuclease, a protease, an amylase, a glycosylase, or a lipase.
20. The method of testing a sample according to claim 1 , wherein the method further comprises, prior to advancing the sample to a lysis chamber, pretreating the sample with a physical treatment.
21. The method of testing a sample according to claim 20 , wherein the physical treatment comprises passing the sample through a size-exclusion filter in a first direction.
22. The method of testing a sample according to claim 20 , wherein the physical treatment comprises exposing the sample to a capture agent immobilized on a solid substrate.
23. The method of testing a sample according to claim 22 , further comprising, after exposure, separating the solid substrate from the sample.
24. The method of testing a sample according to claim 22 , wherein the capture agent is an antibody with affinity for red blood cells.
25. The method of testing a sample according to claim 1 , wherein the sample is sputum and the method further comprises, prior to mixing the sample with the at least one lysis reagent, bead beating the sputum to liquify the sample.
26. The method of testing a sample according to claim 25 , wherein the bead beating comprises mixing the sputum with ceramic, glass, or steel beads.
27. The method of testing a sample according to claim 1 , wherein prior to introducing the enriched nucleic acid into the rehydration chamber and distributing the analyte/reagent solution to two or more assay chambers, the method further comprises passing the enriched nucleic acid through a second porous solid support.