CrAg Testing Research Articles

District and sub-district analysis of cryptococcal antigenaemia prevalence and specimen positivity in KwaZulu-Natal, South Africa.

BackgroundCryptococcal meningitis (CM) is a leading cause of mortality among HIV-positive South Africans. Reflex cryptococcal antigen (CrAg) testing of remnant plasma was offered as a pilot prior to implementation in October 2016 in KwaZulu-Natal province. The national reflex CrAg positivity was 5.4% compared to 7.3% for KwaZulu-Natal.ObjectivesThe aim of this study was to interrogate CrAg positivity by health levels to identify hotspots.MethodData for the period October 2016 to June 2017 were analysed. Health district CrAg positivity and prevalence were calculated, with the latter using de-duplicated patient data. The district CrAg positivity and the number of CrAg-positive specimens per health facility were mapped using ArcGIS. For districts with the highest CrAg positivity, a sub-district CrAg positivity analysis was conducted.ResultsThe provincial CrAg positivity was 7.6%. District CrAg positivity ranged from 5.7% (Ugu) to 9.6% (Umkhanyakude) with prevalence ranging from 5.5% (Ugu) to 9.7% (Umkhanyakude). The highest CrAg positivity was reported for the Umkhanyakude (9.6%) and King Cetswayo (9.5%) districts. In these two districts, CrAg positivity of 10% was noted in the Umhlabuyalingana (10.0%), Jozini (10.2%), uMhlathuze (10.5%) and Nkandla (10.8%) subdistricts. In these subdistricts, 135 CrAg-positive samples were reported for the Ngwelezane hospital followed by 41 and 43 at the Hlabisa and Manguzi hospitals respectively.ConclusionCryptococcal antigen positivity was not uniformly distributed at either the district or sub-district levels, with identified facility hotspots in the Umkhanyakude and King Cetswayo districts. This study demonstrates the value of laboratory data to identify hotspots for planning programmatic interventions.

Opportunistic diseases diminish the clinical benefit of immediate antiretroviral therapy in HIV-tuberculosis co-infected adults with low CD4+ cell counts.

HIV-tuberculosis (TB) co-infection remains an important cause of mortality in sub-Saharan Africa. Clinical trials have reported early (within 2 weeks of TB therapy) antiretroviral therapy (ART) reduces mortality among HIV-TB co-infected research participants with low CD4 cell counts, but this has not been consistently observed. We aimed to evaluate the current WHO recommendations for ART in HIV-TB co-infected patients on mortality in routine clinical settings. We compared two cohorts before (2008-2010) and after (2012-2013) policy change on ART timing after TB and examined the effectiveness of early versus delayed ART on mortality in HIV-TB co-infected participants with CD4 cell count 100 cells/μl or less. We used inverse probability censoring-weighted Cox models on baseline characteristics to balance the study arms and generated hazard ratios for mortality. Of 356 participants with CD4 cell counts 100 cells/μl or less, 180 were in the delayed ART cohorts whereas 176 were in the early ART cohorts. Their median age (32.5 versus 32 years) and baseline CD4 cell counts (26.5 versus 26 cells/μl) respectively were similar. There was no difference in mortality rates of both cohorts. The risk of death increased in participants with a positive Cryptococcal antigen (CrAg) test in both the early ART cohort (aHR = 2.6, 95% CI 1.0-6.8; P = 0.045) and the delayed ART cohort (aHR = 4.2, 95% CI 1.9-9.0; P < 0.001 CONCLUSION:: Early ART in patients with HIV-TB co-infection was not associated with reduced risk of mortality in routine care. Asymptomatic Cryptococcal antigenaemia increased the risk of mortality in both cohorts.

Extent of Lung Involvement and Serum Cryptococcal Antigen Test in Non-Human Immunodeficiency Virus Adult Patients with Pulmonary Cryptococcosis.

Background:Serum cryptococcal antigen (CrAg) test is the most used noninvasive method to detect cryptococcal infection. However, false-negative CrAg test is not uncommon in clinical practice. Then, the aim of this study was to investigate the factors associated with false-negative CrAg test among non-human immunodeficiency virus (HIV) adult patients with pulmonary cryptococcosis and its clinical features.Methods:One hundred and fourteen non-HIV adult patients with pulmonary cryptococcosis, proven by biopsy, were retrospectively reviewed. Finally, 85 patients were enrolled; 56 were CrAg positive (CrAg+ group) and 29 were negative (CrAg− group). It was a cross-sectional study. Then, baseline characteristics, underlying diseases, clinical symptoms, laboratory findings, and chest radiological findings were reviewed and analyzed. Chi-square test was used to analyze categorical variable. Odds ratio (OR) was used to measure correlation. Student's t-test was obtained to analyze continuous variable.Results:No difference in baseline characteristics, underlying diseases, clinical symptoms, and laboratory findings were found between two groups (P > 0.05 in all). Nevertheless, diffuse extent lesion was 82.1% in CrAg+ group and 10.3% in CrAg− group (χ2= 40.34, P < 0.001; OR = 39.87).Conclusions:Among patients with limited pulmonary involvement, a negative serum CrAg does not preclude the diagnosis of pulmonary cryptococcosis. However, among patients with extensive pulmonary involvement, serum CrAg is a useful diagnostic tool for pulmonary cryptococcosis. Furthermore, we also noticed that the untypical and mild presentations with extensive pulmonary lesion might be the features of pulmonary cryptococcosis, which needs further investigation.

Cryptococcal antigen positivity combined with the percentage of HIV-seropositive samples with CD4 counts &lt;100 cells/μl identifies districts in South Africa with advanced burden of disease

IntroductionCryptococcal meningitis (CM) is an opportunistic fungal disease with a high mortality among HIV-positive patients with severe immunosuppression (CD4 count <100 cells/μl). Reflexed screening for cryptococcal antigen (CrAg) in remnant blood samples was initially piloted at selected CD4 testing laboratories of the National Health Laboratory Service (NHLS) prior to the implementation of a national screening programme using a lateral flow assay (LFA) (IMMY, Norman, OK, USA). The aim of this study was to assess CrAg positivity nationally, per province and district in combination with the percentage of CD4 samples tested with a CD4 count <100 cells/μl to identify areas with advanced HIV/CrAg disease burden.MethodsCrAg and CD4 laboratory result data were extracted from the NHLS corporate data warehouse. Monthly test volumes were used to assess CrAg test volumes and coverage, while bubble charts were used to display the relationship between CD4 <100 cells/μl, CrAg positivity and number of positive CrAg samples by district. ArcGIS software was used to spatially report CrAg positivity.ResultsCrAg screening coverage was stable at around 96% after November 2016. Samples with a CD4 <100 cell/μl and CrAg positivity were also stable over the study period at 10% and ~5% respectively. The highest CrAg positivity was reported for the Kwa-Zulu Natal province (7.3%), which also had the lowest percentage of samples with a CD4 <100 cells/μl (7.2%). Uthungulu and Umkhanyakude districts had the highest CrAg positivity (9.3% and 8.9% respectively). Ethekwini and Johannesburg Metro districts contributed to 22% of the total number of CrAg-positive samples tested across South Africa for the period reported.ConclusionExisting CD4 testing services were used to rapidly scale up CrAg reflex testing in South Africa. Districts with advanced HIV and CrAg disease burden were identified that need further investigation of patient management interventions.

Disseminated Cryptococcal Disease of the Bone Marrow, Cerebrospinal Fluid and Blood in an ART-Naive Patient with Advanced HIV: A Case Report

Background: Cryptococcosis affects 10-30% of patients with acquired immunodeficiency syndrome (AIDS) resulting in significant morbidity and mortality. The primary sites of cryptococcal disease are the lung and central nervous system with bone marrow involvement being rare.Case presentation: This case report describes a human immunodeficiency virus (HIV) positive, anti-retroviral therapy (ART) naive female with pancytopenia who demonstrated no significant symptoms nor clinical signs as well as a negative serum cryptococcal antigen (CrAg) test. A bone marrow biopsy was then performed which resulted in a diagnosis of disseminated cryptococcal disease of the bone marrow. Blood and cerebrospinal fluid (CSF) fungal cultures confirmed the presence of Cryptococcus neoformans. The patient was then successfully treated with antifungal agents-amphotericin B and fluconazole.Conclusion: Bone marrow examination may therefore be a useful method in early diagnosis of disseminated cryptococcosis as a cause of cytopenias in immunocompromised patients, thus enabling early appropriate treatment and improved outcomes.

High Cryptococcal Antigen Titers in Blood Are Predictive of Subclinical Cryptococcal Meningitis Among Human Immunodeficiency Virus-Infected Patients.

High mortality rates among asymptomatic cryptococcal antigen (CrAg)-positive patients identified through CrAg screening, despite preemptive fluconazole treatment, may be due to undiagnosed cryptococcal meningitis. Symptoms were reviewed in CrAg-positive patients identified by screening 19233 individuals with human immunodeficiency virus infection and CD4 cell counts <100/µL at 17 clinics and 3 hospitals in Johannesburg from September 2012 until September 2015, and at 2 hospitals until June 2016. Cerebrospinal fluid samples from 90 of 254 asymptomatic patients (35%) and 78 of 173 (45%) with headache only were analyzed for cryptococcal meningitis, considered present if Cryptococcus was identified by means of India ink microscopy, culture, or CrAg test. CrAg titers were determined with stored blood samples from 62 of these patients. The associations between blood CrAg titer, concurrent cryptococcal meningitis, and mortality rate were assessed. Cryptococcal meningitis was confirmed in 34% (95% confidence interval, 25%-43%; 31 of 90) of asymptomatic CrAg-positive patients and 90% (81%-96%; 70 of 78) with headache only. Blood CrAg titer was significantly associated with concurrent cryptococcal meningitis in asymptomatic patients (P < .001) and patients with headache only (P = .003). The optimal titer for predicting cryptococcal meningitis was >160 (sensitivity, 88.2%; specificity, 82.1%); the odds ratio for concurrent cryptococcal meningitis was 34.5 (95% confidence interval, 8.3-143.1; P < .001). About a third of asymptomatic CrAg-positive patients have concurrent cryptococcal meningitis. More effective clinical assessment strategies and antifungal regimens are required for CrAg-positive patients, including investigation for cryptococcal meningitis irrespective of symptoms. Where it is not possible to perform lumbar punctures in all CrAg-positive patients, blood CrAg titers should be used to target those most at risk of cryptococcal meningitis.

Estimating the cost-per-result of a national reflexed Cryptococcal antigenaemia screening program: Forecasting the impact of potential HIV guideline changes and treatment goals.

IntroductionDuring 2016, the National Health Laboratory Service (NHLS) introduced laboratory-based reflexed Cryptococcal antigen (CrAg) screening to detect early Cryptococcal disease in immunosuppressed HIV+ patients with a confirmed CD4 count of 100 cells/μl or less.ObjectiveThe aim of this study was to assess cost-per-result of a national screening program across different tiers of laboratory service, with variable daily CrAg test volumes. The impact of potential ART treatment guideline and treatment target changes on CrAg volumes, platform choice and laboratory workflow are considered.MethodsCD4 data (with counts < = 100 cells/μl) from the fiscal year 2015/16 were extracted from the NHLS Corporate Date Warehouse and used to project anticipated daily CrAg testing volumes with appropriately-matched CrAg testing platforms allocated at each of 52 NHLS CD4 laboratories. A cost-per-result was calculated for four scenarios, including the existing service status quo (Scenario-I), and three other settings (as Scenarios II-IV) which were based on information from recent antiretroviral (ART) guidelines, District Health Information System (DHIS) data and UNAIDS 90/90/90 HIV/AIDS treatment targets. Scenario-II forecast CD4 testing offered only to new ART initiates recorded at DHIS. Scenario-III projected all patients notified as HIV+, but not yet on ART (recorded at DHIS) and Scenario-IV forecast CrAg screening in 90% of estimated HIV+ patients across South Africa (also DHIS). Stata was used to assess daily CrAg volumes at the 5th, 10th, 25th, 50th, 75th, 90th and 95th percentiles across 52 CD4-laboratories. Daily volumes were used to determine technical effort/ operator staff costs (% full time equivalent) and cost-per-result for all scenarios.ResultsDaily volumes ranged between 3 and 64 samples for Scenario-I at the 5th and 95th percentile. Similarly, daily volumes ranges of 1–12, 2–45 and 5–100 CrAg-directed samples were noted for Scenario’s II, III and IV respectively. A cut-off of 30 CrAg tests per day defined use of either LFA or EIA platform. LFA cost-per-result ranged from $8.24 to $5.44 and EIA cost-per-result between $5.58 and $4.88 across the range of test volumes. The technical effort across scenarios ranged from 3.2–27.6% depending on test volumes and platform used.ConclusionThe study reported the impact of programmatic testing requirements on varying CrAg test volumes that subsequently influenced choice of testing platform, laboratory workflow and cost-per-result. A novel percentiles approach is described that enables an overview of the cost-per-result across a national program. This approach facilitates cross-subsidisation of more expensive lower volume sites with cost-efficient, more centralized higher volume laboratories, mitigating against the risk of costing tests at a single site.

Acridine orange fluorescent microscopy is more sensitive than India ink light microscopy in the rapid detection of cryptococcosis among CrAg positive HIV patients.

BackgroundIndia ink microscopy on cerebrospinal fluid is still utilized in resource limited settings for the diagnosis of cryptococcal meningitis despite its poor sensitivity. We hypothesized that staining fungal nucleic acids with fluorescent dyes instead of the capsule with India ink might improve sensitivity for the diagnosis of cryptococcal meningitis.MethodsWe enrolled 96 HIV-infected participants with cryptococcal meningitis who provided 194 CSF specimens at serial time points in Kampala, Uganda. Cryptococcosis was diagnosed by cerebrospinal fluid (CSF) cryptococcal antigen (CrAg) test and only positive samples were included. We stained CSF with India ink and acridine orange. We cultured the same samples on standard fungal media. We compared acridine orange to CrAg, India ink and CSF culture.ResultsAcridine orange was more sensitive (96%) than India ink (79%) with reference to CSF CrAg. Acridine orange and India ink had a statistically significant difference (P<0.001) with a 25% correlation for detection of Cryptococcus yeasts. India ink had more negative results (22%) than acridine orange (4%). The sensitivity for India ink increased (86%) while that of acridine orange did not change (97%) when compared to CSF culture. However, both India ink and acridine orange had poor predictive values with reference to culture.ConclusionAcridine orange is a better alternative to India ink in the rapid detection of cryptococcosis among CrAg positive HIV patients.

Prevalence of cryptococcal infection among advanced HIV patients in Argentina using lateral flow immunoassay.

BackgroundGlobally, Latin America ranks third among regions with most cases of AIDS related cryptococcal meningitis. In 2009, a lateral flow immunoassay (LFA) for the detection of cryptococcal antigen (CrAg) was developed as a potential point-of-care test for diagnosis of cryptococcal infection. In 2011 World Health Organizations recommended on CrAg screening for HIV positive persons with CD4 below 100 cells/μL, followed by preemptive fluconazole treatment. However, in Argentina no formal recommendations for CrAg screening have been issued.MethodsHIV positive patients > = 18 years with advanced immunosuppression (CD4 counts ≤100 cells/μL within 3 months or WHO stage III/IV), who visited the hospital between April 1, 2014 and January 31, 2015, were included. The LFA was performed according to the manufacturer’s instructions on all serum samples. When CrAg detection was positive, a lumbar puncture was performed to rule out cryptococcal meningitis. Patients without evidence of meningeal involvement were treated with preemptive oral fluconazole in ambulatory care.ResultsWe included 123 patients. Prevalence of CrAg-positivity was 8.1%. Among the 10 CrAg-positive patients, 6 had meningeal involvement detected through the CSF analysis (CSF India-ink testing, CSF CrAg and culture). The remaining 4 patients with positive CrAg received targeted preemptive treatment with oral fluconazole and were free of cryptococcal disease during the follow-up period. None of the 113 patients with a negative CrAg test result developed cryptococcal disease.ConclusionsThis is the first study in Argentina, to our knowledge, describing the prevalence of cryptococcosis and usefulness of CrAg screening. LFA provided early diagnosis to determine a high prevalence of CrAg in our hospital, and that screening for subclinical infection with preemptive antifungal treatment, prevented a substantial proportion of meningeal disease.

Establishing a cost-per-result of laboratory-based, reflex Cryptococcal antigenaemia screening (CrAg) in HIV+ patients with CD4 counts less than 100 cells/μl using a Lateral Flow Assay (LFA) at a typical busy CD4 laboratory in South Africa.

IntroductionCryptococcal meningitis is a major cause of mortality and morbidity in countries with high HIV prevalence, primarily affecting patients whose CD4 are < = 100 cells/μl. Routine Cryptococcal Antigen (CrAg) screening is thus recommended in the South African HIV treatment guidelines for all patients with CD4 counts < = 100 cells/μl, followed by pre-emptive anti-fungal therapy where CrAg results are positive. A laboratory-based reflexed CrAg screening approach, using a Lateral Flow Assay (LFA) on remnant EDTA CD4 blood samples, was piloted at three CD4 laboratories.ObjectivesThis study aimed to assess the cost-per-result of laboratory-based reflexed CrAg screening at one pilot CD4 referral laboratory.MethodsCD4 test volumes from 2014 were extracted to estimate percentage of CD4 < = 100 cells/μl. Daily average volumes were derived, assuming 12 months per/year and 21.73 working days per/month. Costing analyses were undertaken using Microsoft Excel and Stata with a provider prospective. The cost-per-result was estimated using a bottom-up method, inclusive of test kits and consumables (reagents), laboratory equipment and technical effort costs. The ZAR/$ exchange of 14.696/$1 was used, where applicable. One-way sensitivity analyses on the cost-per-result were conducted for possible error rates (3%– 8%, reductions or increases in reagent costs as well as test volumes (ranging from -60% to +60%).ResultsThe pilot CD4 laboratory performed 267000 CD4 tests in 2014; ~ 9.3% (27500) reported CD4< = 100 cells/μl, equivalent to 106 CrAg tests performed daily. A batch of 30-tests could be performed in 1.6 hours, including preparation and analysis time. A cost-per-result of $4.28 was reported, with reagents contributing $3.11 (72.8%), while technical effort and laboratory equipment overheads contributed $1.17 (27.2%) and $0.03 (<1%) respectively. One-way sensitivity analyses including increasing or decreasing test volumes by 60% revealed a cost-per-result range of $3.84 to $6.03.ConclusionA cost-per-result of $4.28 was established in a typical CD4 service laboratory to enable local budgetary cost projections and programmatic cost-effectiveness modelling. Varying reagent costs linked to currency exchange and varying test volumes in different levels of service can lead to varying cost-per-test and technical effort to manage workload, with an inverse relationship of higher costs expected at lower volumes of tests.

CRYPTOCOCCAL MENINGOENCEPHALITIS IN HIV-INFECTED PATIENTS IN MADAGASCAR: HIGH PREVALENCE AND LETHALITY AND THERAPEUTIC CHALLENGES

BackgroundIn Madagascar the epidemiology of cryptococcosis is poorly documented. The main objective of this study was to estimate the prevalence of Cryptococcal meningoencephalitis (CM) in Madagascar and to describe the...

High Prevalence of Cryptococcal Antigenaemia and Disseminated Cryptococcal Disease Amongst Patients with Advanced HIV Disease in Pune, India

Background The World Health Organization (WHO) recommends routine cryptococcal antigen (CrAg) screening in patients with advanced HIV disease initiating antiretroviral treatment (ART). India has yet to adopt this strategy as the burden of cryptococcal disease is unknown.Methods This was a prospective cohort study conducted between March 1, 2010 and March 1, 2017 at three private hospitals in Pune, India. All HIV-positive patients (symptomatic and asymptomatic) with CD4 counts ≤ 200 cells/µL were screened for serum cryptococcal antigen. Serum CrAg was measured using latex agglutination (LA) test. Both, ART naïve and ART experienced patients were included in the study. All HIV infected patients who were CrAg-positive were offered lumbar puncture (LP) and worked up for disseminated cryptococcal disease.ResultsA total of 785 HIV-positive patients (24.2% females) were included. Median age of cohort was 42 years (IQR, 35–49) and median CD4 count was 79 cells/mm3 (IQR, 37–82). 182/785(23.2%) patients were ART experienced. A total of 6.75% (53/785) of patients were CrAg positive in serum. Thirty-nine of 53 (73.6%) patients with positive serum cryptococcal antigen test had CD4 count ≤100 cells/mm3 while 14/53 (26.4%) had CD4 between 100 and 200 cells/mm3. Cerebrospinal fluid (CSF) CrAg was positive in 44/53(83%) patients. Two of 53(3.78%) had non-CNS, diffuse pulmonary cryptococcal disease and 7/53(13.2%) patients had isolated cryptococcal antigenemia. Patients with cryptococcal meningitis and crptococcal pulmonary disease were treated with Amphotericin-B plus oral Fluconazole. Patients with isolated cryptococcal antigenemia were treated with oral Fluconazole. Mortality at 6 months for patients with positive CrAg test was 22.6% (12/53).Conclusion We found 6.75% prevalence of cryptococcaemia amongst HIV patients with CD4 <200 cells/mm3. Given the high fatality rates observed, routine CrAg screening should be considered for all Indians with advanced HIV disease.Disclosures All authors: No reported disclosures.

High Prevalence of Cryptococcal Antigenaemia amongst Asymptomatic Advanced HIV Patients in Pune, India

Background: The World Health Organization recommends routine cryptococcal antigen (CrAg) screening in advanced AIDS patients initiating antiretroviral treatment (ART). India has yet to adopt this strategy as the burden of cryptococcal antigenaemia is unknown. Methods: A prospective study was conducted in a large public sector ART centre and the inpatient wards of Sassoon Hospital, Pune, India. All consenting patients >18 years of age with CD4 count <100 cells/mm3 were screened for CrAg by latex agglutination assay. Those with positive CrAg underwent cerebrospinal fluid analysis, chest radiograph and abdominal ultrasound to rule out cryptococcal disease. The impact of CrAg positivity on all-cause mortality was assessed by logistic regression analysis. Results: Amongst 208 AIDS patients with CD4 cells <100 cells/mm3 who underwent CrAg testing, median age was 40 (interquartile range [IQR], 35–49) years, 134 (64%) were male and median CD4 count was 64.5 cells/mm3 (IQR, 37–82). Overall, 16 (8%, 95% confidence interval [CI], 4–12) patients were positive for CrAg, of which 8 (50%) had CD4 cells <50 cells/mm3 and 3 (19%) CrAg-positive patients had incidental cryptococcal meningitis. At 6-month follow-up, the case fatality rate was higher amongst CrAg-positive patients (38%) compared with CrAg-negative patients (18%) (P = 0.06). After adjusting for age, sex, CD4 count and ART, there was a trend towards increased all-cause mortality (adjusted OR, 3.18, 95% CI, 0.60–16.88, P = 0.17). Conclusions: We found an 8% prevalence of cryptococcaemia amongst adult AIDS patients with CD4 cells <100 cells/mm3. Given the high fatality rates observed, routine screening for CrAg should be considered for all Indian persons with advanced HIV disease.

Brief Report: Geographical Variation in Prevalence of Cryptococcal Antigenemia Among HIV-Infected, Treatment-Naive Patients in Nigeria: A Multicenter Cross-Sectional Study.

Worldwide, HIV-associated cryptococcal meningitis affects approximately 1 million persons and causes 600,000 deaths each year mostly in sub-Saharan Africa. Limited data exist on cryptococcal meningitis and antigenemia in Nigeria, and most studies are geographically restricted. We determined the prevalence of cryptococcal antigenemia (CrAg) among HIV-infected, treatment-naive individuals in Nigeria. This was a retrospective, cross-sectional study across 4 geographic regions in Nigeria. We performed CrAg testing using a lateral flow immunoassay on archived whole-blood samples collected from HIV-infected participants at US President's Emergency Plan for AIDS Relief (PEPFAR)-supported sites selected to represent the major geographical and ethnic diversity in Nigeria. Eligible samples were collected from consenting patients (>15 years) naive to antiretroviral therapy with CD4 count less than 200 cells per cubic millimeter and were stored in an -80°C freezer. A total of 2752 stored blood samples were retrospectively screened for CrAg. Most of the samples were from participants aged 30-44 years (57.6%), and 1570 (57.1%) were from women. The prevalence of CrAg positivity in specimens with CD4 <200 cells per cubic millimeter was 2.3% (95% confidence interval: 1.8% to 3.0%) and varied significantly across the 4 regions (P < 0.001). At 4.4% (3.2% to 5.9%), the South East contained the highest prevalence. The significant regional variation in CrAg prevalence found in Nigeria should be taken into consideration as plans are made to integrate routine screening into clinical care for HIV-infected patients.

Screening HIV-Infected Patients with Low CD4 Counts for Cryptococcal Antigenemia prior to Initiation of Antiretroviral Therapy: Cost Effectiveness of Alternative Screening Strategies in South Africa.

BackgroundIn 2015 South Africa established a national cryptococcal antigenemia (CrAg) screening policy targeted at HIV-infected patients with CD4+ T-lymphocyte (CD4) counts <100 cells/ μl who are not yet on antiretroviral treatment (ART). Two screening strategies are included in national guidelines: reflex screening, where a CrAg test is performed on remnant blood samples from CD4 testing; and provider-initiated screening, where providers order a CrAg test after a patient returns for CD4 test results. The objective of this study was to compare costs and effectiveness of these two screening strategies.MethodsWe developed a decision analytic model to compare reflex and provider-initiated screening in terms of programmatic and health outcomes (number screened, number identified for preemptive treatment, lives saved, and discounted years of life saved) and screening and treatment costs (2015 USD). We estimated a base case with prevalence and other parameters based on data collected during CrAg screening pilot projects integrated into routine HIV care in Gauteng, Free State, and Western Cape Provinces. We conducted sensitivity analyses to explore how results change with underlying parameter assumptions.ResultsIn the base case, for each 100,000 CD4 tests, the reflex strategy compared to the provider-initiated strategy has higher screening costs ($37,536 higher) but lower treatment costs ($55,165 lower), so overall costs of screening and treatment are $17,629 less with the reflex strategy. The reflex strategy saves more lives (30 lives, 647 additional years of life saved). Sensitivity analyses suggest that reflex screening dominates provider-initiated screening (lower total costs and more lives saved) or saves additional lives for small additional costs (< $125 per life year) across a wide range of conditions (CrAg prevalence, patient and provider behavior, patient survival without treatment, and effectiveness of preemptive fluconazole treatment).ConclusionsIn countries with substantial numbers of people with untreated, advanced HIV disease such as South Africa, CrAg screening before initiation of ART has the potential to reduce cryptococcal meningitis and save lives. Reflex screening compared to provider-initiated screening saves more lives and is likely to be cost saving or have low additional costs per additional year of life saved.

Implementation and Operational Research: Evaluation of a Public-Sector, Provider-Initiated Cryptococcal Antigen Screening and Treatment Program, Western Cape, South Africa.

Screening for serum cryptococcal antigen (CrAg) may identify those at risk for disseminated cryptococcal disease (DCD), and preemptive fluconazole treatment may prevent progression to DCD. In August 2012, the Western Cape Province (WC), South Africa, adopted provider-initiated CrAg screening. We evaluated the implementation and effectiveness of this large-scale public-sector program during its first year, September 1, 2012-August 31, 2013. We used data from the South African National Health Laboratory Service, WC provincial HIV program, and nationwide surveillance data for DCD. We assessed the proportion of eligible patients screened for CrAg (CrAg test done within 30 days of CD4 date) and the prevalence of CrAg positivity. Incidence of DCD among those screened was compared with those not screened. Of 4395 eligible patients, 26.6% (n = 1170) were screened. The proportion of patients screened increased from 15.9% in September 2012 to 36.6% in August 2013. The prevalence of positive serum CrAg was 2.1%. Treatment data were available for 13 of 24 CrAg-positive patients; 9 of 13 were treated with fluconazole. Nine (0.8%) incident cases of DCD occurred among the 1170 patients who were screened for CrAg vs. 49 (1.5%) incident cases among the 3225 patients not screened (P = 0.07). Relatively few eligible patients were screened under the WC provider-initiated CrAg screening program. Unscreened patients were nearly twice as likely to develop DCD. CrAg screening can reduce the burden of DCD, but needs to be implemented well. To improve screening rates, countries should consider laboratory-based reflexive screening when possible.

Evolution of Cryptococcal Antigen Testing: What is new?

Over the last decade, an upsurge in both the frequency and severity of fungal infections due to the HIV/AIDS epidemic and the use of immunosuppressive therapy has occurred. Even diagnostic methods like culture and microscopy, which have low sensitivity and longer turn-around-times are not widely available, leading to delays in timely antifungal therapy and detrimental patient outcomes. The evolution of cryptococcal antigen (CrAg) testing to develop inexpensive and more sensitive methods to detect cryptococcal antigen is significant. These newer tests employ immunoassays as part of point-of-care platforms, which do not require complex laboratory infrastructure and they have the potential to detect early disease and reduce time to diagnosis of cryptococcal infection. Advocacy for widely available and efficacious life-saving antifungal treatment should be the only remaining challenge.

Evaluation of screening and treatment of cryptococcal antigenaemia among HIV-infected persons in Soweto, South Africa.

We retrospectively evaluated clinic-based screening to determine the prevalence of cryptococcal antigenaemia and management and outcome of patients with antigenaemia. Cryptococcal antigen (CrAg) screening of HIV-infected adults who attended the HIV clinic at Chris Hani Baragwanath Hospital was conducted over 19 months. Data collected from CrAg-positive patients included CD4 T-lymphocyte count at screening, prior or subsequent cryptococcal meningitis (CM), antifungal and antiretroviral treatment and outcome after at least 8 months. Of 1460 patients with no prior CM, 30 (2.1%) had a positive CrAg test. The prevalence of antigenaemia among patients with a CD4 count < 100 cells/μl and no prior CM was 2.8% (20 of 708). Of 29 evaluable CrAg-positive patients with no prior CM, 14 (48%) did not return for post-screening follow-up. Of these 14, five developed CM and one (7%) was known to be alive at follow-up. Of 15 patients who returned for follow-up, two already had evidence of nonmeningeal cryptococcosis. Overall, 11 received fluconazole, one did not and fluconazole treatment was unknown for three. Among these 15, one developed CM and 10 (67%) were known to be alive at follow-up. Overall, 18 (62%) of 29 CrAg-positive patients died or were lost to follow-up. Seven (0.5%) of 1430 CrAg-negative patients developed CM a median of 83 days post-screening (range 34 to 219 days). Loss to follow-up is the major operational issue relevant to scale-up of screen-and-treat. Patient outcomes may be improved by rapid access to CrAg results and focus on linkage to and retention in HIV care.

Performance of cryptococcal antigen lateral flow assay using saliva in Ugandans with CD4

BackgroundCryptococcal meningitis can best be diagnosed by cerebrospinal fluid India ink microscopy, cryptococcal antigen detection, or culture. These require invasive lumbar punctures. The utility of cryptococcal antigen detection in saliva is unknown. We evaluated the diagnostic performance of the point-of-care cryptococcal antigen lateral flow assay (CrAg LFA) in saliva.MethodsWe screened HIV-infected, antiretroviral therapy naïve persons with symptomatic meningitis (n = 130) and asymptomatic persons with CD4+<100 cells/µL entering into HIV care (n = 399) in Kampala, Uganda. The diagnostic performance of testing saliva was compared to serum/plasma cryptococcal antigen as the reference standard.ResultsThe saliva lateral flow assay performance was overall more sensitive in symptomatic patients (88%) than in asymptomatic patients (27%). The specificity of saliva lateral flow assay was excellent at 97.8% in the symptomatic patients and 100% in asymptomatic patients. The degree of accuracy of saliva in diagnosing cryptococcosis and the level of agreement between the two sample types was better in symptomatic patients (C-statistic 92.9, κ-0.82) than in asymptomatic patients (C-statistic 63.5, κ-0.41). Persons with false negative salvia CrAg tests had lower levels of peripheral blood CrAg titers (P<0.001).ConclusionThere was poor diagnostic performance in testing saliva for cryptococcal antigen, particularly among asymptomatic persons screened for preemptive treatment of cryptococcosis.

Prevalence and Outcomes of Cryptococcal Antigenemia in HIV-Seropositive Patients Hospitalized for Suspected Tuberculosis in Uganda

Cryptococcal infection occurs in HIV-seropositive patients and is associated with high mortality. However, limited information is available on the prevalence and outcomes of cryptococcal antigenemia among hospitalized HIV-seropositive patients in sub-Saharan Africa. To determine the prevalence of and risk factors for cryptococcal antigenemia among HIV-seropositive patients presenting to Mulago Hospital (Kampala, Uganda) with unexplained cough ≥2 weeks and suspected tuberculosis (TB) and also to determine if antigenemia is associated with an increased mortality. Between September 2009 and September 2010, we enrolled consecutive HIV-seropositive adults hospitalized at Mulago Hospital with cough ≥2 weeks and suspected TB. Banked serum was tested for cryptococcal antigen. We compared demographic and clinical characteristics, and 2-month mortality in patients with and without cryptococcal antigenemia. Of 563 HIV-seropositive patients, 32 (5.7%) were cryptococcal antigen (CrAg) positive. None had Cryptococcus neoformans detected on fungal culture of bronchoalveolar lavage fluid (n = 116). CrAg-positive patients had a lower median CD4 count compared with CrAg-negative patients (25 vs. 55 cells/μL, P = 0.02), and a substantial proportion of CrAg-positive patients also had concurrent TB (31%). A positive CrAg test was not associated with increased mortality during the 2-month follow-up period (hazard ratio: 0.99, 95% confidence interval: 0.63 to 1.54, P = 0.95) after adjusting for CD4 count and antiretroviral therapy use at enrollment and/or follow-up. Occult cryptococcal antigenemia occurs commonly among hospitalized HIV-seropositive patients with suspected TB. CrAg testing should be considered in hospitalized HIV-seropositive patients with CD4 count <50 cells/μL, coupled with longer follow-up to evaluate the diagnostic value of CrAg and therapeutic interventions in patients with asymptomatic cryptococcal antigenemia.