Secondary analysis of malaria rapid diagnostic tests from rounds 5–8 of WHO product testing with a focus on false-negative results

Despite the widespread use of malaria rapid diagnostic test (RDT) in clinical practice, there are a lot of challenges. We conducted a secondary analysis of 129 malaria RDT data from rounds 5–8 of the World Health Organization (WHO) product testing summary and discuss the causes of false-negative (FN) results with a focus on low parasite density, improper RDT storage, operation and interpretation, and plasmodium falciparum with a pfhrp2/3 gene deletion. The results demonstrated that the malaria RDTs currently commercially available might cause FN results in practice.

Quality of Malaria and HIV Rapid Diagnostic Test kits (RDTs) in health facilities and medicines outlets in the Greater Accra Region of Ghana

Background: Questions remain on the quality of malaria and HIV Rapid Diagnostic Test kits (RDTs) stocked and used in health facilities in Ghana. The Food and Drugs Authority (FDA) in Ghana is mandated to regulate RDTs for quality. By this, all RDTs must be registered, and each brand given a unique registration number. This study aimed to assess the quality of malaria and HIV RDTs in health facilities in the Greater Accra Region of Ghana, using FDA standards. Method: Data was obtained using structured questionnaire from 400 facilities in three districts in the Greater Accra region. A multi-stage sampling procedure was used to select the health facilities including retail medicine outlets. Information on the registration status of the RDTs and conditions under which they were stored were gathered. RDTs kept in air conditioned or well-ventilated rooms were considered as being stored under good condition. RDTs, registered by the FDA and appropriately stored were considered to be of good quality. Data was coded, stored, and analyzed using STATA version 15. Results: About 17% of the malaria RDTs stocked in the pharmacies were unregistered, 85.7% in hospitals were registered. Also, 83.3% of HIV RDTs in the Policlinics were registered. Registration status of the RDTs were associated with the districts in which the health facilities were located (p = 0.006). The RDTs were generally stored under good conditions (99.5%). Over forty percent (41.9%) of user practitioners interviewed rated the quality of the malaria RDTs as good and 59.2% rated HIV RDTs as very good. Conclusion: Though there were some unregistered RDTs whose quality cannot be ascertained, the quality of malaria and HIV RDTs in the facilities assessed were rated as good and likely to produce good results for malaria and HIV case detection.

Field Performances of Rapid Diagnostic Tests Detecting Human Plasmodium Species: A Systematic Review and Meta-Analysis in India, 1990–2020

Rapid diagnostic tests (RDTs) have become a mainstay of malaria diagnosis in endemic countries since their implementation in the 1990s. We conducted a 30-year systematic review and meta-analysis on malaria RDTs performance in India. Outcomes of interest were sensitivity (Se), specificity (Sp), positive/negative likelihood ratio (PLR/NLR), and diagnostic odd ratio (DOR). Among the 75 studies included, most of the studies were cross-sectional (65.3%), hospital-based (77.3%), and targeted febrile patients (90.6%). Nearly half of RDTs were designed for detecting Plasmodium falciparum only (47.5%) while the rest were for P. falciparum and P. vivax (11.9%), and P. falciparum/Pan-Plasmodium except for P. knowlesi (32.3%). When compared to light microscopy (gold standard), pooled estimates of performances were: Se = 97.0%, Sp = 96.0%, PLR = 22.4, NLR = 0.02 and DOR = 1080. In comparison to polymerase chain reaction, the RDTs showed Se = 89.0% and Sp = 99.0%. Performance outcomes (Se and Sp) were similar for RDT targeting P. falciparum only, but decreased for mixed and non-falciparum infections. Performances of malaria RDTs are still high India. However, there is a need for developing RDTs with regard to targeting minor malarial species, individuals carrying only mature gametocytes, and pfhrp2-deleted parasites.

Secondary Analysis on Malaria RDTs in WHO Product Testing from Round 5 to 8 on False Negative Results in Testing Sample

Background with the widespread use of malaria rapid diagnostic tests (RDTs) in clinical practice, they also show their own challenges. Compared with most of the attention focusing on false positive results in WHO product testing, the same important false negative results attract insufficient focus. Method data of 129 malaria RDTs in the summary of WHO rounds 5 to 8 product testing was secondary analyzed in 5 aspects including low parasite density, improper RDTs storage, operation and interpretation, P. falciparum (Pf) with pfhrp2/3 genes deletion, inter-lot variation. Results First, the percentage of tests that achieved a panel detection score (PDS) < 80% at a low parasite density was 20-25% for Pf, and substantially higher for P. vivax (Pv). Second, Some Pv- and Pf- detecting products showed an increasing deterioration with increase of storage temperature. Third, approximately 20-27% products’ performances were unsatisfied in blood safety and instruction quality; and 30-35% test bands of the RDTs for Pf were barely visible, and the ones for Pv returned a higher proportion of weak band intensity. Fourth, different Lots of each test products may produce inconsistent results. Fifth, many malaria RDTs obtained a low PDS (< 50%) and a high false negative rate (> 50%) when testing Pf with deletion of pfhrp2/3 gene. Conclusion the malaria RDTs currently widely used were overestimated and could cause false negative results in practice. The clinicians should be aware of these shortcomings in order to draw more accurate diagnosis and treatment.

The use of dried tube specimens of Plasmodium falciparum in an external quality assessment programme to evaluate health worker performance for malaria rapid diagnostic testing in healthcare centres in Togo

Background The use of rapid diagnostic tests (RDTs) to diagnose malaria is common in sub-Saharan African laboratories, remote primary health facilities and in the community. Currently, there is a lack of reliable methods to ascertain health worker competency to accurately use RDTs in the testing and diagnosis of malaria. Dried tube specimens (DTS) have been shown to be a consistent and useful method for quality control of malaria RDTs; however, its application in National Quality Management programmes has been limited. Methods A Plasmodium falciparum strain was grown in culture and harvested to create DTS of varying parasite density (0, 100, 200, 500 and 1000 parasites/µL). Using the dried tube specimens as quality control material, a proficiency testing (PT) programme was carried out in 80 representative health centres in Togo. Health worker competency for performing malaria RDTs was assessed using five blinded DTS samples, and the DTS were tested in the same manner as a patient sample would be tested by multiple testers per health centre. Results All the DTS with 100 parasites/µl and 50% of DTS with 200 parasites/µl were classified as non-reactive during the pre-PT quality control step. Therefore, data from these parasite densities were not analysed as part of the PT dataset. PT scores across all 80 facilities and 235 testers was 100% for 0 parasites/µl, 63% for 500 parasites/µl and 93% for 1000 parasites/µl. Overall, 59% of the 80 healthcare centres that participated in the PT programme received a score of 80% or higher on a set of 0, 500 and 1000 parasites/ µl DTS samples. Sixty percent of health workers at these centres recorded correct test results for all three samples. Conclusions The use of DTS for a malaria PT programme was the first of its kind ever conducted in Togo. The ease of use and stability of the DTS illustrates that this type of samples can be considered for the assessment of staff competency. The implementation of quality management systems, refresher training and expanded PT at remote testing facilities are essential elements to improve the quality of malaria diagnosis.

The use of dried tube specimens of Plasmodium falciparum in an external quality assessment programme to evaluate health worker performance for malaria rapid diagnostic testing in healthcare centres in Togo

BackgroundThe use of rapid diagnostic tests (RDTs) to diagnose malaria is common in sub-Saharan African laboratories, remote primary health facilities and in the community. Currently, there is a lack of reliable methods to ascertain health worker competency to accurately use RDTs in the testing and diagnosis of malaria. Dried tube specimens (DTS) have been shown to be a consistent and useful method for quality control of malaria RDTs, however, its application in National Quality Management programmes has been limited.MethodsA Plasmodium falciparum strain was grown in culture and harvested to create DTS of varying parasite density (0, 100, 200, 500 and 1,000 parasites/µL). Using the dried tube specimens as quality control material, a proficiency testing (PT) programme was carried out in 80 representative health centres in Togo. Health worker competency for performing malaria RDTs was assessed using five blinded DTS samples, and the DTS were tested in the same manner as a patient sample would be tested by multiple testers per health centre. ResultsAll the DTS with 100 parasites/µl and 50% of DTS with 200 parasites/µl were classified as non-reactive during the pre-PT quality control step. Therefore, data from these parasite densities were not analysed as part of the PT dataset. PT scores across all 80 facilities and 235 testers was 100% for 0 parasites/µl, 63% for 500 parasites/µl and 93% for 1,000 parasites/µl. Overall, 59% of the 80 healthcare centres that participated in the PT programme received a score of 80% or higher on a set of 0, 500 and 1,000 parasites/ µl DTS samples. Sixty percent of health workers at these centres recorded correct test results for all three samples.ConclusionsThe use of DTS for a malaria PT programme was the first of its kind ever conducted in Togo. The ease of use and stability of the DTS illustrates that they this type of samples can be considered for the assessment of staff competency. The implementation of quality management systems, refresher training and expanded PT at remote testing facilities are essential elements to improve the quality of malaria diagnosis.

STUDY OF THREE MALARIA RAPID DETECTION TESTS AND ITS CORRELATION WITH PARASITIC INDEX FOR P.FALCIPARUM AND P.VIVAX

Objective: To determine the sensitivity and specificity of three Malaria rapid antigen detection tests(RDTs) .To study the sensitivity of the RDTs in relation to parasitic index . Materials and Methods: The study was conducted at a tertiary care hospital. Peripheral smear were prepared and stained.Parasite index was calculated. Three rapid antigen detection tests ; Optimal – IT, Paramax-3 and QDx malaria PAN/PF were tested. Results: Sensitivity for Optimal – IT was highest (98.47%). QDx malaria PAN/Pf gave highest specificity (97%). All the three RDTs gave sensitivity of 100% at a parasitic index of more than 100 parasites per µl. Sensitivity of Optimal – IT and QDx malaria PAN/Pf for P falciparum and P vivax was 100% and 88.88% respectively at a parasitic index of 51-100 parasites/ µl. Conclusion: Malaria RDTs are a good diagnostic tool in health care set ups where quick results are desired and expert microscopy is not available.

The use of dried tube specimens of Plasmodium falciparum in an External Quality Assessment program to evaluate health worker performance for malaria rapid diagnostic testing in healthcare centers in Togo

Background: The use of rapid diagnostic tests (RDTs) to diagnose malaria is common in Sub-Saharan African laboratories, remote primary health facilities and in the community. Currently, there is a lack of reliable methods to ascertain health worker competency to accurately use RDTs in the testing and diagnosis of malaria. Dried tube specimens (DTS) have been shown to be a consistent and useful method for quality control of malaria RDTs, however, its application in National Quality Management programs has been limited.Methods: A P. falciparum strain was grown in culture and harvested to create DTS of varying parasite density (0, 100, 200, 500 and 1,000 parasites/µL). Using the dried tube specimens as quality control material, a proficiency testing (PT) program was carried out in 80 representative health centers in Togo. Health worker competency for performing malaria RDTs (mRDTs) was assessed using five blinded DTS samples, and the DTS were tested in the same manner as a patient sample would be tested by multiple testers per health center. Results: All the DTS with 100 parasites/µl and 50% of DTS with 200 parasites/µl were classified as non-reactive during the pre-PT quality control step. Therefore, data from these parasite densities were not analyzed as part of the PT dataset. PT scores across all 80 facilities and 235 testers was 100% for 0 parasites/µl, 63% for 500 parasites/µl and 93% for 1,000 parasites/µl. Overall, 59% of the 80 healthcare centers that participated in the PT program received a score of 80% or higher on a set of 0, 500 and 1,000 parasites/ µl DTS samples. Sixty percent of health workers at these centers recorded correct test results for all three samples. Conclusions: The use of DTS for a malaria PT program was the first of its kind ever conducted in Togo. The ease of use and stability of the DTS illustrates that they this type of samples can be considered for the assessment of staff competency. The implementation of quality management systems, refresher training and expanded PT at remote testing facilities are essential elements to improve the quality of malaria diagnosis.

Impact of Plasmodium falciparum gene deletions on malaria rapid diagnostic test performance

Background Malaria rapid diagnostic tests (RDTs) have greatly improved access to diagnosis in endemic countries. Most RDTs detect Plasmodium falciparum histidine-rich protein 2 (HRP2), but their sensitivity is seriously threatened by the emergence of pfhrp2-deleted parasites. RDTs detecting P. falciparum or pan-lactate dehydrogenase (Pf- or pan-LDH) provide alternatives. The objective of this study was to systematically assess the performance of malaria RDTs against well-characterized pfhrp2-deleted P. falciparum parasites. Methods Thirty-two RDTs were tested against 100 wild-type clinical isolates (200 parasites/µL), and 40 samples from 10 culture-adapted and clinical isolates of pfhrp2-deleted parasites. Wild-type and pfhrp2-deleted parasites had comparable Pf-LDH concentrations. Pf-LDH-detecting RDTs were also tested against 18 clinical isolates at higher density (2,000 parasites/µL) lacking both pfhrp2 and pfhrp3. Results RDT positivity against pfhrp2-deleted parasites was highest (> 94%) for the two pan-LDH-only RDTs. The positivity rate for the nine Pf-LDH-detecting RDTs varied widely, with similar median positivity between double-deleted (pfhrp2/3 negative; 63.9%) and single-deleted (pfhrp2-negative/pfhrp3-positive; 59.1%) parasites, both lower than against wild-type P. falciparum (93.8%). Median positivity for HRP2-detecting RDTs against 22 single-deleted parasites was 69.9 and 35.2% for HRP2-only and HRP2-combination RDTs, respectively, compared to 96.0 and 92.5% for wild-type parasites. Eight of nine Pf-LDH RDTs detected all clinical, double-deleted samples at 2,000 parasites/µL. Conclusions The pan-LDH-only RDTs evaluated performed well. Performance of Pf-LDH-detecting RDTs against wild-type P. falciparum does not necessarily predict performance against pfhrp2-deleted parasites. Furthermore, many, but not all HRP2-based RDTs, detect pfhrp2-negative/pfhrp3-positive samples, with implications for the HRP2-based RDT screening approach for detection and surveillance of HRP2-negative parasites.

The Use Of Dried Tube Specimens Of Plasmodium Falciparum In An External Quality Assessment Program To Evaluate Health Worker Performance For Malaria Rapid Diagnostic Testing In Healthcare Centers In Togo

Background: The use of rapid diagnostic tests (RDTs) to diagnose malaria is common in Sub-Saharan African laboratories, remote primary health facilities and in the community. Currently, there is a lack of reliable methods to ascertain health worker competency to accurately use RDTs in the testing and diagnosis of malaria. Dried tube specimens (DTS) have been shown to be a consistent and useful method for quality control of malaria RDTs, however, its application in National Quality Management programs has been limited. Methods: A P. falciparum strain was grown in culture and harvested to create DTS of varying parasite density (0, 100, 200, 500 and 1,000 parasites/µL). Using the dried tube specimens as quality control material, a proficiency testing (PT) program was carried out in 80 health centers in Togo. Health worker competency for performing malaria RDTs (mRDTs) was assessed using five blinded DTS samples, and the DTS were tested in the same manner as a patient sample would be tested by multiple testers per health center. Results: All the DTS with 100 parasites/µl and 50% of DTS with 200 parasites/µl were classified as non-reactive during the pre-PT quality control step. Therefore, data from these parasite densities were not analyzed as part of the PT dataset. PT scores across all 80 facilities and 235 testers was 100% for 0 parasites/µl, 63% for 500 parasites/µl and 93% for 1,000 parasites/µl. Overall, 59% of the 80 healthcare centers that participated in the PT program received a score of 80% or higher on a set of 0, 500 and 1,000 parasites/ µl DTS samples. Sixty percent of health workers at these centers scored higher than 80%. Conclusions: The use of DTS for a malaria PT program was the first of its kind ever conducted in Togo. The ease of use of the DTS illustrates that they can serve as well-characterized, stable samples to assess staff competency. The implementation of quality management systems, refresher training and expanded PT at remote testing facilities are essential elements to improve the quality of malaria diagnosis.