Blood spot collection

Response rates for blood spot collection instead of blood samples

Many studies routinely collect buccal cell samples as their DNA source, however blood spots offer increased versatility for serum analytes as well as DNA. Dried blood spots are easy and economical to collect, ship, store, and process, but response rates to this alternative collection method were not known. Further, the offer of an incentive could increase response, but this was also not known. Among those who had previously declined to provide a blood sample, we randomized 400 persons to receive a small incentive or no incentive and divided our recruitment effort into those who had or had not been diagnosed with breast cancer. We found that collecting blood spots was an economical alternative and boosted response rates among both cases and non-cases. The small incentive increased response in the cases but not the non-cases.