APCR Screening: Everyone?

Our recent series of discussions and comments on the efficacy of D-dimer results in superficial thrombophlebitis for factor V Leiden (FVL) mutation patients has pointed us to a thoughtful discussion of the value of screening unselected populations for activated protein C resistance (APCR), the condition that correlates closely with FVL. Dr. Emmanual Favaloro’s current article; Favaloro EJ, McDonald D. Futility of testing for factor V Leiden. Blood Transfusion 2012; 10: 260–3 DOI 10.2450/2012.0097-12, provides the American College of Medical Genetics current guidelines for directed FVL screens, and reminds readers that the guidelines do not recommend generalized screening. The article also records a steady trend towards increased FVL testing with a parallel drop in the percentage of positive results, suggesting that ordering patterns are becoming indiscriminate. His article is framed as a debate in Blood Transfusion, and will appear in the next issue, which will appear online in August, 2012. For more detail, see also Favaloro EJ, Mohammed S, Pati N, Ho MY, McDonald. A clinical audit of congenital thrombophilia investigation in tertiary practice. Pathology 2011;43:266–72. 
I’d like to “hear” some opinions from our participants about the efficacy of generalized FVL screening using the APCR assay. Do you advocate that everyone be screened, or do you advocate that we screen all potential blood donors to protect them or their recipients from the risk of thrombosis?
Additionally, Dr. F employs a dilute Russell viper venom time (DRVVT)-based assay for APCR, Siemens ProC Ac R, (formerly Dade-Behring) whose clinical characteristic he describes favorably in Favaloro EJ, Orsag I, Bukuya M, McDonald D. A 9-year retrospective assessment of laboratory testing for activated protein C resistance: evolution of a novel approach to thrombophilia investigations. Pathology 2002;34:348–55. I’ve only known of partial thromboplastin time (PTT)-based assays, and wonder whether anyone reading this is using the DRVVT-based assay?

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