GLOBAL HEALTH
Designing and Implementing a Proficiency Testing
Program for Cryptococcus Antigen in Uganda
By Lucy Atieno, PhD, APHL Consultant; Elizabeth Toure, MPH, senior specialist Global Health and Samantha Musumeci, MPH, specialist, Global Health
Cryptococcus neoformans and Cryptococcus
gatii are environmental opportunistic
fungi that can cause cryptococcosis, a
condition that manifests in the lungs and
central nervous system. With over one
million people living with HIV in Uganda,
rapid Cryptococcus antigen (CrAg) testing
for those who are immunocompromised
is critical for timely treatment. In Uganda,
the CrAg lateral flow assay (LFA) has been
successfully implemented in several
facilities across the laboratory tiered
system. To assure the validity of test
results, the Ministry of Health (MOH) and
CDC Uganda engaged APHL’s expertise to
develop a CrAg LFA proficiency testing (PT)
program.
To support the MOH in ensuring the
competence of personnel performing
the qualitative IMMY CrAg ® LFA,
APHL set up a national PT scheme
at Uganda’s National Microbiology
Reference Laboratory (NMRL). To assess
the readiness of NMRL for this project,
a gap analysis was completed which
focused on the laboratory environment,
laboratory safety, availability of biological
materials, specimen management,
quality assurance, human resources, data
management and logistics. Based on this
audit, the laboratory was deemed capable
of supporting a CrAg PT program.
Phased Implementation
The first phase of the project involved
technical activities such as writing
standard operating procedures (SOPs),
process mapping and workstation
setup, media preparation, preparation
of negative and positive panels, method
standardization and verification.
The second phase focused on data
management, SOP revision and overall
review of the program for improvement
opportunities.
The timeline for implementation of this
project was six weeks and culminated
in a pilot PT distribution with 22
laboratories from across the laboratory
tiered system. A site map consisting of
PublicHealthLabs
@APHL
NMRL staff package the Cryptococcus Antigen Proficiency
Testing panels for distribution
laboratory location and distance from
NMRL was developed to facilitate efficient
distribution of panels to these facilities.
PT coordinators from NMRL went out
to all sites at the onset of the project to
sensitize personnel on the project and the
use of the data collection tools.
Plasma was acquired from the national
blood bank and used as a base matrix
once it had been screened and deemed
negative for CrAg. Positive samples were
made by spiking the base matrix with
a standard strain of C. neoformans at
different concentrations to create strong
and weak positive panels. The method of
panel preparation was standardized for
uniformity and a representative sample
of all prepared panels was verified before
distribution.
In concordance with NMRL, the panel
distribution schedule was established on a
quarterly basis using the National Sample
Transport and Result Network. Each PT
panel contained three tubes consisting
of one negative, one strong positive and
one weak positive sample. Laboratories
were required to handle these samples
in the same manner as other samples
received in the laboratory. Participating
sites were expected to submit results
within a two-week period after receiving
the panels.
APHL.org
top: The IMMY CrAg LFA is tested during spiking experiments
and production of positive proficiency testing panels
bottom: Dr. Lucy Atieno process maps the Cryptococcus
Antigen Proficiency Testing program with NMRL staff
Pilot Results and Next Steps
Out of the 22 laboratories in this pilot
study, the response rate was 82%.
Fourteen facilities (63.6%) obtained
satisfactory results while eight (36.4%)
obtained unsatisfactory results. The
laboratories with unsatisfactory results
underwent corrective action to resolve
the errors impacting the quality of their
results. The PT pilot results indicate
that there is a need for monitoring the
performance of the CrAg LFA. The
NMRL is now capable of managing the
CrAg PT program and will continue
to provide quarterly PT panels and
supervision for sites to ensure that
patients are receiving quality results
and appropriate treatment. n
Fall 2019 LAB MATTERS
29