Table 1.
Percent of samples by characteristics related to validity of DBS assays in the US Health and Retirement Study, 2016 (N = 3321)
| Percent | |
|---|---|
| Quality of DBS cards | |
| Multiple drops | 19.9 |
| Smeared drops | 29.0 |
| Overlapping spots | 18.5 |
| Incorrectly placed desiccant | 5.4 |
| Quality of individual spots | |
| Overlapping, smeared spot | |
| Total cholesterol | 3.4 |
| HDL cholesterol | 3.4 |
| HbA1c | 0.4 |
| CRP | 2.9 |
| Cystatin C | 2.9 |
| Small spot | |
| Total cholesterol | 24.7 |
| HDL cholesterol | 24.1 |
| HbA1c | 8.2 |
| CRP | 26.3 |
| Cystatin C | 27.5 |
| High temperature (≥90 °F) | 24.2 |
| High humidity (≥90%) | 12.7 |
| Days before freezing (DBS) | |
| 0–2 days | 10.6 |
| 3 days | 20.0 |
| 4‐5 days | 38.6 |
| 6‐7 days | 20.4 |
| 8+ days | 10.4 |
Abbreviations: CRP, C‐reactive protein; DBS, dried blood spot; HbA1c, glycosylated hemoglobin; HDL, high‐density lipoprotein.