Poster Presentation 20th Lancefield International Symposium on Streptococci and Streptococcal Diseases 2017

Is dried blood spot (DBS) a real-world alternative to serum sampling for the collection of blood penicillin levels? (#210)

Madhu Page-Sharp 1 , Laurens Manning 2 3 , Robert M Hand 3 4 , Kevin T Batty 1
  1. School of Pharmacy and Curtin Health Innovation Research Institute, Curtin Univeristy of Technology, Perth, Western Australia, Australia
  2. School of Medicine and Pharmacology, University of Western Australia, Perth, Western Australia, Australia
  3. Fiona Stanely Hospital, Murdoch, Western Australia, Australia
  4. Telethon Kids Institute, University of Western Australia, Subiaco, Western Australia, Australia


DBS are well established for testing several different drug levels. DBS for penicillin has been developed to assist with pharmacokinetic studies in children, however the stability of DBS has not been validated.  DBS, like other methods still require freezing for long term storage.


To assess the reliability of DBS as an alternative for collecting blood penicillin levels in real world scenarios.


Fresh heparinsed blood was collected and spiked with penicillin (1mg/L) and dispensed on to standard protein saver cards (40µL/spot).  All samples were then placed in an air tight container with desiccant. Samples were exposed to a range of temperatures to mimic real collection scenarios and degradation was assessed; refrigeration (4°C), room temperature (22°C), hot room (35°C), and hot car (45°C).  An esky (with ice bricks) and portable fridge (Waeco) sampling was also conducted with exposure to 45°C ambient temperature.


At 4°C and the portable fridge (10°C), there was no significant penicillin degradation at 8 hours.  Room temperature showed minimal degradation (1.5%) at 8 hours.  Esky with ice-bricks expose to 45°C for 8 hours showed a 2.5% degradation of penicillin.  When dried in hot environments DBS showed accelerated degradation of penicillin (>5%) at 2.5hours (35°C) and less than 1 hour (45°C).


When using DBS to assess penicillin levels, keeping temperatures <22°C or <10°C allow approximately 6 hours and 8 hours of sample stability respectively.  These results validate the use of the DBS penicillin assay as a viable alternative to traditional collection methods in clinical practice.