Re: Changes to malaria rapid diagnostic tests (RDT) lot-testing protocol of the WHO-FIND malaria RDT
evaluation programme ─ Reduction in frequency of interval testing
Requests for lot-testing of malaria RDTs at the laboratories supported for this purpose by WHO and
FIND increased significantly during 2010 with a further rapid increase in requests in the first half of 2011.
This is anticipated to continue. This is resulting in increasing strains on both the availability of panel
samples used for testing, and space requirements at the laboratories for storage of RDTs. The current
lot-testing protocol requires re-testing at 6-monthly intervals over the remaining shelf life of the lot
During the last steering committee meeting in London in May, 2011, WHO and FIND reviewed the
programme with a number of major users. The primary aim of the review was to maintain open access
to lot-testing for public-sector procurers of malaria RDTs and ensure results are reliable, whilst keeping
within current budgets. The programme has now accumulated considerable data on results of lottesting.
It is noted that, while interval testing (testing of RDTs after storage at a temperature near the
recommended maximum at 6-montly intervals) provided valuable independent data on real-time
product stability valuable for long-term procurement decisions, the impact on the field use of individual
lots under test was limited. Failures during interval testing have been few, and those that have occurred
have not been early enough to impact on field use of the lot. However, this part of the testing regimen
has high resource requirements.
After consultation with major users, it has been decided to restrict interval testing to one episode at
18 months after receipt of tests; reduced to 12 months for products with less than 18 months
remaining shelf-life at time of receipt. The protocol for the 18 month interval testing will be the same
as currently used for 6, 12 , 18 month testing (i.e. number of RDTs, number of samples).
Initial testing will remain unchanged. This change in procedure will enable a reduction in the number of
tests required for testing, as specified below, and a considerable reduction in the number required to be
incubated, as requirements of additional tests for confirmatory testing of stored lots will be reduced.
Test type
P falciparum only
Combination test
(or pan-specific test with single test line)
Current requirement
New requirement
Note: Explanation of revised numbers of RDTs to be submitted. The initial evaluation on receipt of RDTs required far
more RDTs than subsequent interval testing, as it is more thorough (see SOPs in the Methods Manual Version 6;
Therefore, removing 2 interval tests (and testing at 18 months only) does not greatly reduce the number of tests
required, but greatly reduces the incubator space required for each lot. For example, 38 RDT are tested for a Pf test
in initial testing, plus spare for repeat testing and for confirmatory testing if the lot does not pass initial evaluation.
For interval testing, only 8 RDTs are used (plus a similar number in reserve for failures).
Further, in view of the current uncertainty regarding continuation of the lot-testing programme after
the end of 2011 related to the anticipated funding short-fall for the RDT evaluation programme, it is
noted that the 18 month interval test of RDTs submitted from this time, and those previously submitted,
will only take place after the end of 2011 if sufficient funding can be identified to support for the
programme. The programme cannot at present assure users that lots can be re-tested after the end of
The changes to interval testing will be put in place from August 8, 2011. Testing of all lots currently
under testing will also be restricted to testing only at 18 months from that date. Requestors will be
reminded when requesting lot testing that only initial testing of all lots submitted can be guaranteed. A
modified example request form is attached.
These changes are being put in place to ensure maximum value for users of the programme and
maintain the high standards of quality of testing at the reference laboratories at RITM and IPC. We
appreciate your understanding. Please don’t hesitate to write if you have any questions or would like
further discussion. Thank you for your understanding.
A new version of the Methods Manual reflecting the above changes to the lot-testing SOPs will be made
available as soon as possible.
Addresses for correspondence
[email protected]
Jane Cunningham
Special Programme for
Research & Training in
Tropical Diseases (TDR)
World Health Organization
Avenue Appia 20
1211 Geneva 27
[email protected]
David Bell
Foundation for Innovative New
Diagnostics (FIND)
Avenue de Budé 16
1202 Geneva
[email protected]
Nora Champouillon
Lot-test coordinator
Foundation for Innovative New
Diagnostics (FIND)
Avenue de Budé 16
1202 Geneva
[email protected]