Table 1.
Controllable and uncontrollable variables that can impact blood-biomarker findings within Alzheimer’s disease studies
| Controllable Variables | Uncontrollable Variables |
|---|---|
| Time of collection | Demographic characteristics (age, sex, ethnicity/race) |
| Fasting status | ApoE ε4 (and other genes) |
| Needle size & location of draw | Smoking status |
| Handling of tubes (e.g. inversions) | Gestation |
| Tube type and additives | Diet |
| Tube collection order | Medications |
| Time of sample in collection tube | Non-AD comorbidities |
| Centrifugation parameters | Alcohol use |
| Time from collection to freeze | Activity level |
| Temperature of freeze | |
| Freeze-thaw cycles | |
| Aliquot size |