Abstract
Purpose :
Autologous serum tears (AST) are produced from serum obtained by blood draw and utilized to treat severe keratoconjunctivitis sicca and dry eye diseases including chronic ocular graft vs host disease (GVHD) and Sjögren’s. Unsuccessful production of AST can occur due to solidified plasma after centrifuging. Retrospective chart review was used to identify patient cases with presumed fibrinogen clots and risk factors that may be associated with the inability to produce autologous serum tears.
Methods :
From January 2019 to December 2022, 99 patients received AST produced at Mayo Clinic in Arizona. IRB-approved retrospective chart review was performed to obtain patient demographics, medical diagnoses, available past laboratory results, prescribed medications, and recent events surrounding blood draws. Laboratory blood draw and pharmacy eye drop production procedures were observed in-person.
Results :
Ten fibrinogen clot episodes occurred in 4 patients who each had multiple unsuccessful production of AST. The fibrinogen clot has a clear to cloudy yellow color with a gel-like consistency instead of the usual liquid serum (Figure 1). Mean age at time of production issue was 64 years old. 3 out of the 4 patients were female. Indication for need for AST was chronic ocular GVHD (3) and Sjögren (1). 8 out of the 10 episodes had recent events of either systemic infection (7) or pulmonary embolism (1). All 4 patients were treated with anticoagulation and/or antiplatelet medications at the time of the draw including rivaroxaban (2), apixaban (2), aspirin (2), and low-molecular-weight heparin (1). Chart review of available laboratory studies showed no clear pattern in abnormal findings.
Conclusions :
The current recommendation is resting test tubes for 30 minutes after blood draw to allow clotting prior to centrifugation separating liquid serum. Inadequate clotting during this stasis period results in fibrinogen being suspended in the serum, leading to solidified plasma that cannot be diluted to produce AST. This sequela would be more of an issue in patients on anti-coagulation or anti-platelet medications. Preliminary protocol change of waiting 60 minutes after blood draw in one affected patient on antiplatelet medication was successful. Results are limited by the small sample size. Analysis of phlebotomy protocol is recommended to confirm longer processing period prior to centrifugation for problems noted in AST production.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.