Data Collection Notes
Training of Field Staff
ZIMSTAT staff and a variety of experts from government ministries, NGOs, and donor organizations participated in a three-day training of trainers session conducted from 30 June to 2 July 2010. Immediately following this training session, pretest training and fieldwork took place. For two weeks in July 2010, 16 participants were trained to administer both paper and electronic questionnaires, take anthropometric measurements, and collect blood samples for anaemia and HIV testing. A representative from the NMRL assisted in training participants on use of finger pricks for blood collection and on proper handling and storage of dried blood spots for HIV testing. The pretest fieldwork was conducted over four days and covered approximately 100 households. Debriefing sessions were held with the pretest field staff, and modifications to the questionnaires were made based on lessons drawn from the exercise.
ZIMSTAT recruited and trained 125 people for the main fieldwork to serve as supervisors, deputy supervisors, interviewers, and reserve interviewers. Training of field staff for the main survey was conducted during a four-week period in late August and September 2010. The training course consisted of instruction regarding interviewing techniques and field procedures, a detailed review of questionnaire content, instruction on how to administer the paper and electronic questionnaire, instruction and practice in weighing and measuring children, mock interviews between participants in the classroom, and practice interviews with real respondents in areas outside the 2010-11 ZDHS sample points. In addition, interviewers who were assigned as team biomarker technicians completed field practice in anthropometry, anaemia testing, and blood collection. Team supervisors and deputy supervisors were trained in data quality control procedures, fieldwork coordination, and use of special programs for the PDAs. Deputy supervisors were also trained in using Global Positioning System (GPS) receivers to obtain coordinates for sample clusters.
Fifteen interviewing teams carried out data collection for the 2010-11 ZDHS. Each team consisted of one team supervisor, one deputy supervisor, three female interviewers, three male interviewers, and one driver. Three of the interviewers on each team also served as biomarker technicians. Electronic data files were transferred from each interviewer’s PDA to the team supervisor’s PDA each day. Thirteen senior staff members from ZIMSTAT coordinated and supervised fieldwork activities. Electronic data files were transferred to ZIMSTAT staff PDAs during field visits. Participants in fieldwork monitoring also included a survey technical specialist, a consultant, and two data processing staff from the MEASURE DHS project as well as representatives from other organisations supporting the survey, including NMRL, UNFPA, USAID, and ZNFPC. Data collection took place over a six-month period, from 29 September 2010 through late March 2011.
Anthropometry, Anaemia, and HIV Testing
The 2010-11 ZDHS incorporated three “biomarkers”: anthropometry, anaemia testing, and HIV testing. In contrast to the data collection procedure for the household and individual interviews, data related to biomarkers were initially recorded on a paper form (the Biomarker Data Collection Form) and subsequently entered into the PDA. The protocol for anaemia testing and for blood specimen collection for HIV testing was reviewed and approved by the Medical Research Council of Zimbabwe (MRCZ), the Institutional Review Board of ICF Macro (now ICF International), and the CDC.
In all households, height and weight measurements were recorded for children age 0-59 months, women age 15-49, and men age 15-54. Anaemia testing. Blood specimens for anaemia testing were collected from all children age 6-59 months, women age 15-49, and men age 15-54 who voluntarily provided written consent to be tested. Blood samples were drawn from a drop of blood taken from a finger prick (or a heel prick in the case of children age 6-12 months with especially small or thin fingers) and collected in a microcuvette. Haemoglobin analysis was carried out on site using a battery-operated portable HemoCue analyzer. Results were provided verbally and in writing. Parents of children with a haemoglobin level under 7 g/dl were instructed to take the child to a health facility for follow-up care. Likewise, nonpregnant women, pregnant women, and men were referred for follow-up care if their haemoglobin levels were below 7 g/dl, 9 g/dl, and 9 g/dl, respectively. All households in which anthropometry and/or anaemia testing was conducted were given a brochure explaining the
causes and prevention of anaemia.
ZDHS biomarker technicians collected blood specimens for laboratory testing of HIV from all women age 15-49 and men age 15-54 who provided written consent to be tested. The protocol for blood specimen collection and analysis was based on the anonymous linked protocol developed for MEASURE DHS. This protocol allows for merging of HIV test results with the sociodemographic data collected in the individual questionnaires after removal of all information that could potentially identify an individual. Interviewers explained the procedure, the confidentiality of the data, and the fact that the test results would not be made available to the respondent. If a respondent consented to HIV testing, five blood spots from the finger prick were collected on a filter paper card to which a barcode label unique to the respondent was affixed. A duplicate label was attached to the Biomarker Data Collection Form. A third copy of the same barcode was affixed to the Blood Sample Transmittal Form to track the blood samples from the field to the laboratory.
Respondents were asked whether they would consent to having the laboratory store their blood sample for future unspecified testing. If respondents did not consent to additional testing using their sample, it was indicated on the Biomarker Data Collection Form that they refused additional tests, and the words “no additional testing” were written on the filter paper card. Each household, whether individuals consented to HIV testing or not, was given an informational brochure on HIV/AIDS and a list of fixed sites providing voluntary counselling and testing services in surrounding districts within the province.
Blood samples were dried overnight and packaged for storage the following morning. Samples were periodically collected in the field, along with the completed questionnaires, and transported to ZIMSTAT in Harare to be logged in and checked; they were then transported to the National Microbiology Reference Laboratory (NMRL) in Harare.
Once it arrived at NMRL, each blood sample was logged into the CSPro HIV Test Tracking System database, given a laboratory number, and stored at -20°C until tested. The HIV testing protocol stipulated that blood could be tested only after questionnaire data collection had been completed, data had been verified and cleaned, and all unique identifiers other than the anonymous barcode number had been removed from the data file. The algorithm called for testing all samples on the first assay test, an enzyme-linked immunosorbent assay (ELISA), the Ani Labsystems HIV EIA.
A negative result was considered negative. All samples with positive results were subjected to a second ELISA, the Vironostika® HIV Uni-Form II Plus O (Biomerieux). Positive samples on the second test were considered positive. If the first and second tests were discordant, a third confirmatory test, the HIV 2.2 western blot (DiaSorin), was administered. The final result was considered positive if the western blot confirmed it to be positive and negative if the western blot confirmed it to be negative. If the western blot results were indeterminate, the sample was considered indeterminate.