Today, though, a patient from New Jersey came in with a bottle of autologous serum that was made for him by an un-named group who said it was ok to keep the bottle in his pocket. He was told it did not have to be refrigerated. It had an “isotonic preservative,” and was not told anything else.
I am very suspicious.
We are culturing the bottle to see if there is bacteria in the bottle: I suspect there is.
It was likely preserved with a non-preserved tear like PuriLens, which by itself is a good tear. It is non-preserved, has an “isotonic preservative” which just means that the solution has the same osmotic pressure as the surrounding cells.
Autologous serum is known to have antimicrobial properties but the effectiveness has not been quantified for diluted serum, which is how most patients are given autologous serum. But autologous serum can become a breading ground for bacteria if not properly used. Thus the multiple vials need to be frozen unless one is using one of the vials, it is kept in the refrigerator only for the 5-7 days, and then tossed out. Serum growth factors are generally acceptable for 6 months when the serum is kept frozen, but the literature indicates that the growth factors decrease as time goes on: best effect is if used within 3 months of the serum being made.
Many papers note that serum can breed bacteria, particularly if left at room temperature. Multiple studies have noted the risk of infection with autologous serum in patients with active epithelial defects (ie, scratched or damaged corneas). It is very rare to have a corneal infection with autologous serum precisely because serum does have antimicrobial properties and key growth factors that heal damaged cells—if the serum is kept refrigerator, frozen and the tip of the bottle does not touch a dirty surface.
If the culture comes back normal, I will be shocked.
Hope to let you all know soon.