Rapid diagnostic tests (RDTs) represent an alternative to microscopy for malaria diagnosis and have shown high sensitivity and specificity in a variety of study settings. Current World Health Organization (WHO) guidelines for quality control of RDTs provide detailed instructions on pre-field testing, but offer little guidance for quality assurance once RDTs are deployed in health facilities. From September 2006 to April 2007, we introduced a histidine-rich protein II (HRP2)-based RDT (Paracheck) for suspected malaria cases five years of age and older in nine health facilities in Rufiji District, Tanzania, to assess sensitivity and specificity of RDTs in routine use at rural health facilities. Thick blood smears were collected for all patients tested with RDTs and stained and read by laboratory personnel in each facility. Thick smears were subsequently reviewed by a reference microscopist to determine RDT sensitivity and specificity. In all nine health facilities, there were significant problems with the quality of staining and microscopy. Sensitivity and specificity of RDTs were difficult to assess given the poor quality of routine blood smear staining. Mean operational sensitivity of RDTs based on reference microscopy was 64.8%, but varied greatly by health facility, range 18.8-85.9%. Sensitivity of RDTs increased with increasing parasite density. Specificity remained high at 87.8% despite relatively poor slide quality. Institution of quality control of RDTs based on poor quality blood smear staining may impede reliable measurement of sensitivity and specificity and undermine confidence in the new diagnostic. There is an urgent need for the development of alternative quality control procedures for rapid diagnostic tests that can be performed at the facility level.
Objective: To determine the pattern of occurrence of salivary gland tumours in Tanzania over a period of twenty years. Design: Cross-sectional retrospective study. Setting: Two referral centres; Muhimbili National Hospital (MNH) and Kilimanjaro Christian Medical Centre (KCMC). Methods: Medical records of patients who presented with tumours of the salivary glands in the two major referral centres over a period of twenty years from 1982 to 2001 were reviewed. Data regarding demographic, clinical and histologic information was analysed. Results: Salivary gland tumours constituted 6.3% of all oral-facial tumours and tumour like lesions. Among the salivary gland tumours, 54% were benign and 46% malignant, which occurred in 80 males and 53 females. Peak age was between 20 and 49 years, with a malefemale ratio of 1.5:1 (p< 0.05). Pleomorphic adenoma was the commonest occurring tumour (44.4%) followed by adenoid cystic carcinoma (24.8%), mucoepidermoid carcinoma (9.8%) and adenocarcinoma (6.5%). Among the benign tumours, pleomorphic adenoma dominated (83.9%), followed by adenoma (9.9%). Among malignant tumours adenoid cystic carcinoma occurred in 54.3% followed by mucoepidemoid carcinoma (22.9%) and adenocarcinoma (11.4%). The parotid gland was the commonest site of occurrence followed by the palate. At initial stages the only complaint from the patients was essentially a slowly growing painless swelling. Treatment modality was mainly surgical in both benign and malignant tumours, however, for malignant tumours radiotherapy alone or in combination with surgery was sometimes employed. Conclusion: On average salivary gland tumours occurred at a relatively younger age compared to that reported in Western countries. Contrary to reports from Europe and America, adenoid cystic carcinoma was the most frequently occurring malignant salivary gland tumour. Late presentation was seen as a problem that needs to be addressed in order to maximise the effectiveness of treatment.
† In the WHO evaluation, parasite detection rate was defined as the percentage of malaria samples in a test panel giving a positive result by two RDTs per lot at the lower parasite density (200 parasites/µL), and a single RDT per lot at the higher parasite density (2,000 or 5,000 parasites/µL). Thus, it is a combined measure of positivity rate, along with inter-test and inter-lot consistency. Abstract. Histidine-rich protein II (HRP2)-based malaria rapid diagnostic tests (RDTs) have shown high sensitivity and specificity for detecting Plasmodium falciparum malaria in a variety of study settings. However, RDTs are susceptible to heat and humidity and variation in individual performance, which may affect their use in field settings. We evaluated sensitivity and specificity of RDTs during routine use for malaria case management in peripheral health facilities. From December 2007 to October 2008, HRP2-based ParaHIT-f RDTs were introduced in 12 facilities without available microscopy in Rufiji District, Tanzania. Health workers received a single day of instruction on how to perform an RDT and thick blood smear. Job aids, Integrated Management of Childhood Illness guidelines, and national malaria treatment algorithms were reviewed. For quality assurance (QA), thick blood smears for reference microscopy were collected for 2 to 3 days per week from patients receiving RDTs; microscopy was not routinely performed at the health facilities. Slides were stained and read centrally within 72 hours of collection by a reference microscopist. When RDT and blood smear results were discordant, blood smears were read by additional reference microscopists blinded to earlier results. Facilities were supervised monthly by the district laboratory supervisor or a member of the study team. Ten thousand six hundred fifty (10,650) patients were tested with RDTs, and 51.5% (5,488/10,650) had a positive test result. Blood smear results were available for 3,914 patients, of whom 40.1% (1,577/3,914) were positive for P. falciparum malaria. Overall RDT sensitivity was 90.7% (range by facility 85.7-96.5%) and specificity was 73.5% (range 50.0-84.3%). Sensitivity increased with increasing parasite density. Successful implementation of RDTs was achieved in peripheral health facilities with adequate training and supervision. Quality assurance is essential to the adequate performance of any laboratory test. Centralized staining and reading of blood smears provided useful monitoring of RDT performance. However, this level of QA may not be sustainable nationwide.
Rapid diagnostic tests (RDTs) were developed as an alternative to microscopy for malaria diagnosis. The RDTs detect malaria parasite antigen(s) in whole blood with high sensitivity and specificity. We assessed health worker malaria treatment practices after the introduction of RDTs in peripheral health facilities without microscopy. From December 2007 to October 2008, we introduced histidine-rich protein II (HRP-2)-based ParaHIT RDTs for routine use in 12 health facilities in Rufiji District, Tanzania. Health workers received training on how to perform RDTs for patients 5 years of age or older with fever or suspected malaria. Children < 5 years of age were to be treated empirically per national guidelines. Among the 30,195 patients seen at these 12 health facilities, 10,737 (35.6%) were tested with an RDT for malaria. 88.3% (9,405/10,648) of tested patients reported fever or history of fever and 2.7% (289/10,677) of all tested individuals were children < 5 years of age. The RDT results were recorded for 10,650 patients (99.2%). Among the 5,488 (51.5%) RDT-positive patients, 5,256 (98.6%) were treated with an appropriate first-line antimalarial per national guidelines (artemether-lumefantrine or quinine). Among the 5,162 RDT-negative patients, only 205 (4.0%) were treated with an antimalarial. Other reported treatments included antibiotics and antipyretics. Implementation of RDTs in rural health facilities resulted in high adherence to national treatment guidelines. Patients testing negative by RDT were rarely treated with antimalarials. Unapproved antimalarials were seldom used. Health workers continued to follow guidelines for the empiric treatment of febrile children.
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