Macroprolactin reactivities in prolactin assays: an issue for clinical laboratories and equipment manufacturers.

was performed in 150 mL of a 1 g/L silver nitrate solution for 10 min at room temperature with gentle shaking. The gel was rinsed twice with distilled water to remove excess silver solution and was developed in a solution containing, per liter, 15g of NaOH, 0.1 g of NaBH4, and 0.48 g of formaldehyde. The gel was first washed in 150 mL of this solution (for ;30 s) to precipitate the excess silver, and then was incubated in 150 mL of the same solution, with gentle shaking, until the bands were visualized (;20 min). The stain was fixed with an aqueous solution of 7.5 g/L NaCO3 for 10 min at room temperature with gentle shaking. The gel was laid on a bench top and covered with Whatman 3MM paper. The Whatman paper was picked up and turned over, so that the gel was peeled off the bench top. The gel was covered with Saran Cling Wrap and stored at 4 °C (up to 2 weeks) or dried under reduced pressure for 1.5 h at 80 °C. We believe this procedure is useful both for its economical cost and for its sensitivity.