Table 3. Cerebrospinal Fluid Cutoffs for Maximal Discrimination Between Normal Cognition and Mild Cognitive Impairment by Race Using Receiver Operating Characteristic Curve Analyses.
| Race by CSF Biomarker | Cutoff (95% CI)a | Sensitivity | Specificity | PPV | NPV |
|---|---|---|---|---|---|
| African American | |||||
| Aβ1-42 level, pg/mL | 208 (126-321) | 0.39 | 0.74 | 0.67 | 0.48 |
| Tau level, pg/mL | 51 (31-59) | 0.39 | 0.82 | 0.74 | 0.51 |
| Tau to Aβ1-42 ratio | 0.17 (0.13-0.46) | 0.5 | 0.66 | 0.66 | 0.5 |
| pTau181 level, pg/mL | 12 (12-19) | 0.62 | 0.62 | 0.68 | 0.55 |
| pTau181 to Aβ1-42 ratio | 0.05 (0.03-0.12) | 0.44 | 0.70 | 0.66 | 0.49 |
| White | |||||
| Aβ1-42 level, pg/mL | 197 (183-245) | 0.55 | 0.85 | 0.77 | 0.68 |
| Tau level, pg/mL | 59 (56-92) | 0.66 | 0.72 | 0.68 | 0.7 |
| Tau to Aβ1-42 ratio | 0.23 (0.22-0.33) | 0.74 | 0.72 | 0.70 | 0.75 |
| pTau181 level, pg/mL | 20 (12-27) | 0.57 | 0.78 | 0.69 | 0.66 |
| pTau181 to Aβ1-42 ratio | 0.05 (0.05-0.13) | 0.78 | 0.65 | 0.67 | 0.77 |
Abbreviations: Aβ1-42, β-amyloid 1-42; CSF, cerebrospinal fluid; NPV, negative predictive value; PPV, positive predictive value; pTau181, phosphorylated tau 181.
a
Calculated using logistic regression with receiver operating characteristic curve analysis to maximize Youden J index (the largest vertical distance from the uninformative diagonal line). The 95% CIs are calculated using bootstrap with sampling (×1000). Covariate-adjusted cutoffs are provided in eTable in the Supplement.