Quantification of neurofilament light chain in physiological samples
The present disclosure relates to immunoassays for NF-L performed on liquid samples derived from physiological fluids such as venous blood to detect the presence or absence of a physiological condition by quantifying one or a combination of NF-L determinations at concentrations indicative of the condition.
1. A method of testing for a neurological condition in a human subject, comprising:
i) forming a liquid sample by diluting a blood or plasma sample taken from the subject in a diluent, wherein the diluent comprises one or more immunoglobulins, a detergent, urea, and one or more blocking agents;
ii) obtaining a concentration of neurofilament light chain (NF-L) in the liquid sample via a singleplex immunoassay or a single molecule array;
iii) comparing the NF-L concentration from the human subject with a NF-L concentration from a healthy control sample; and
iv) assigning a risk of the neurological condition based on the comparison of step iii), wherein an increase in the NF-L concentration from the human subject compared to the NF-L concentration from the healthy control is indicative of the neurological condition.
2. The method of claim 1 , wherein the neurological condition is a neurodegenerative disease.
3. The method of claim 1 , wherein the neurological condition is an Alzheimer's disease.
4. The method of claim 1 , wherein the neurological condition is a multiple sclerosis.
5. The method of claim 1 , wherein the singleplex immunoassay or the single molecule array are digital assays.
6. The method of claim 1 , wherein the method further comprises: determining whether a CT scan of the subject is positive or negative for the neurological condition prior to performing the immunoassay.
7. The method of claim 1 , wherein the method is used in place of a CT scan and/or an MRI scan in a diagnostic protocol.
8. The method of claim 1 , wherein the assigning comprises determining a ratio of the NF-L concentration from the human subject compared to the NF-L concentration from the healthy control.
9. The method of claim 1 , wherein the comparing of step iii) further comprises calculating at least one classification value based on a classification model using the obtained concentration of NF-L as an input to the classification model; and wherein the assigning of step iv) further comprises comparing the at least one classification value to at least one threshold value.
10. The method of claim 9 , wherein the calculating at least one classification value comprises determining a ratio of the NF-L concentration from the human subject compared to the NF-L concentration from the healthy control.
11. The method of claim 1 , wherein the one or more immunoglobulins comprises human IgG, bovine gamma globulin (BgG), or a combination thereof.
12. The method of claim 1 , wherein the one or more blocking agents comprises mouse IgG.
13. The method of claim 11 , wherein the human IgG is at a concentration of between 1 mg/mL and 10 mg/mL.
14. The method of claim 9 , wherein the classification model predicts a traumatic brain injury with a receiver operating characteristic (ROC) curve having an area under the curve (AUC) of at least 0.85.
15. The method of claim 9 , wherein the classification model predicts a traumatic brain injury with a true positive rate of at least 75% at a false positive rate of less than 25%.
16. The method of claim 11 , wherein the one or more immunoglobulins comprises the combination of human IgG and bovine gamma globulin (BgG).
17. The method of claim 12 , wherein the one or more immunoglobulins comprises human IgG, bovine gamma globulin (BgG), or a combination thereof.
18. The method of claim 17 , wherein the one or more immunoglobulins comprises the combination of human IgG and bovine gamma globulin (BgG).
19. The method of claim 18 , wherein the human IgG is at a concentration of between 1 mg/mL and 10 mg/mL.