using field-friendly technologies, the dhs program is able to collect biomarker data relating to conditions and infections. dhs surveys have tested for anemia (by measuring hemoglobin), hiv infection, sexually transmitted diseases such as syphilis and the herpes simplex virus, serum retinol (vitamin a), lead exposure, high blood pressure, and immunity from vaccine-preventable diseases like measles and tetanus. traditionally, much of the data gathered in dhs surveys is self-reported. biomarkers complement this information by providing an objective profile of a specific disease or health condition in a population. biomarker data contributes to the understanding of behavioral risk factors and determinants of different illnesses.