also known as Potassium in Serum or Plasma
| # | Retailer | Lab | Seen | Price | |
|---|---|---|---|---|---|
| 1 | Goodlabscheapest via Quest · seen today | Quest | today | $3 | order → |
| 2 | Jason Health via Quest · seen today | Quest | today | $5 | order → |
| 3 | DirectLabs via Quest Diagnostics · seen today | Quest Diagnostics | today | $26 | order → |
| 4 | LabsMD seen today |
| Vitamin B12 | 16 retailers | $10 |
| Magnesium RBC Test | 14 retailers | $8 |
| Ferritin | 14 retailers | $9 |
| Calcium, Ionized | 14 retailers | $18 |
| Iodine Test | 13 retailers | $30 |
| Selenium | 12 retailers | $12 |
| Iron Test | 11 retailers | $13 |
| Zinc, Blood Test | 11 retailers | $11 |
| — |
| today |
| $53 |
| order → |