Most rapid diagnostic test (RDT) kits are packaged with single-use disposable blood transfer devices (BTDs) used to collect, transfer and deposit a specified amount of blood – usually in the range of 5 to 50 µL – from a fingerprick to a sample well on the RDT cassette. Blood transfer can be a challenging part of the process; for example, volume control can be prone to error. The concerns about many BTDs include (i) risk of blood spillage and exposure to infectious blood; (ii) incorrect amount of blood (too much can lead to a red background in the results window, too little can lead to false negative test results); and (iii) the blood transfer device is complex and not user-friendly for health workers in low resource settings.
Over the years, published studies have demonstrated a great deal of variation in consistency and accuracy of blood volume delivered by commercially available BTDs on malaria RDTs1. In response to this, FIND co-developed (together with Injection 74, France) and evaluated an ‘inverted cup’ device for easy transfer of 5 µL blood to malaria RDTs in 2011. Field studies conducted in Nigeria, the Philippines and Uganda have shown that this new device achieved the highest overall performance in terms of accuracy of blood volume, blood safety, ease of use, and user preference2,3.
This improved BTD is being used by more and more malaria RDT users and manufacturers, with an astonishing 250 million inverted cup BTDs distributed in 2017. One of the major RDT manufacturers commented, “It is safe to say that most end-users prefer inverted cups over pipettes”, and another said “The inverted cup has been indeed very revolutionary in blood collection and has been accepted well by most customers.”
Building on this success, FIND has now developed the ‘conical cup’ BTD for 23 µL of blood to allow the use with RDTs like the HIV or HAT rapid tests. A recently published study has demonstrated the success of this device when used by primary level health care staff in Uganda4. As one health worker put it, “with the conical cup, I have seen it is very easy because it is just a matter of touching the blood which then comes up by itself and then just transferring it on the pad.”
The design of both devices make them very easy to use, without the need of volume control, and very little risk of blood exposure for the health worker. More details can be found in the published studies below. In case of questions, please contact Sandra Incardona (firstname.lastname@example.org) or Bertrand Schutz at Injection 74 (email@example.com).
1. An assessment of various blood collection and transfer methods used for malaria rapid diagnostic tests. Luchavez et al, Malaria Journal (2007)
2. Blood transfer devices for malaria rapid diagnostic tests: evaluation of accuracy, safety and ease of use. Hopkins et al, Malaria Journal (2011)
3. The inverted cup device for blood transfer on malaria RDTs: ease of use, acceptability and safety in routine use by health workers in Nigeria. Incardona et al, Malaria Journal (2018)
4. Accuracy, Ease of Use, and Acceptability of a 23-µL Conical Cup Blood Transfer Device for Use with Rapid Diagnostic Tests. Incardona et al, Am J Trop Med Hyg (2018)
- FIND’s other malaria projects