This essay is part of the Volumetric Sovereignty forum.

eople in Nicaragua with a form of progressive renal failure called chronic kidney disease of non-traditional causes (CKDnt) talk in volumes about their condition. I don’t mean that they go on and on about their aches and pains. Most of the thousands of CKDnt patients in Nicaragua were sugarcane plantation workers until they got sick. Complaining isn’t really something a plantation worker has time for. Cañeros get paid for harvesting a daily allotment, what they call tarea. If you don’t complete your tarea, your field manager can half your daily pay. Tarea is measured in square meters, but once you’re slashing away at the stalks of cane, it becomes clear that tarea is actually three-dimensional. Readers may recall that the title of Sidney Mintz’s classic book on the subject is Worker in the Cane, not Worker on the Cane.

But this essay is not so much about the violence of plantation labor as about the violence of its aftermath. In the past two decades, the rate of kidney failure in Nicaragua has skyrocketed, and the epidemic of CKDnt among cañeros accounts for much of that increase.

Like other renal patients, cañeros with CKDnt have come to understand their kidneys as fellow volumetric workers. The kidneys filter waste from blood into urine. A number called the “estimated glomerular filtration rate” (eGFR) is a central metric of this function. According to global diagnostic standards, kidney disease begins when the eGFR drops below 60. Living with CKDnt, then, means becoming conscious of an internal volumetric dysfunction. Managing the volume of liquid that goes into one’s body—and the diminishing volume of urine that one can excrete—becomes essential to survival. In the later stages of CKDnt, when the kidneys fail altogether, surviving requires dialysis (Nading 2018), an elaborate mechanical replication of the kidney’s filtering work.

Sugar companies carefully screen workers each year, and they refuse to employ anyone with an eGFR below 60. This means that the disease, which tends to set in between the ages of 30 and 40, is accompanied by diminished income, stress, and depression. Nicaragua has an institutional mechanism for addressing these psychosocial effects, the National Institute of Social Security (INSS). By law, cañeros must put a portion of their biweekly paychecks into an INSS account. In the event of a work-related illness or injury, they can expect access to marginally better clinical care, along with a full pension to offset losses in pay. The INSS was founded in the 1950s on the model of European social safety nets, but most of its benefits accrue to the roughly 25% of Nicaraguans who are formally employed and pay into the system. This low volume means that the INSS is chronically underfunded and notoriously uneven in meeting its welfare obligations.

Here is where filtration becomes biopolitical. Sugar companies refuse work to anyone with an eGFR below 60, but this does not mean that they take responsibility for their condition. In fact, a CKDnt patient’s access to INSS pension benefits depends on the opinion of doctors in INSS clinics. According to Nicaraguan diagnostic standards, in each case, doctors must categorize the onset of CKDnt as either work-related (laboral) or ordinary (común). The laboral/común divide, like the myriad diagnostic codes that govern global health, is a filtering device. Calling CKDnt laboral permits a patient to petition for INSS disability benefits, and a full pension. Calling it común permits the patient only to a reduced pension—the same as one might get on voluntary early retirement.

A report diagnosing CKDnt as “laboral”. Photo by Author

In the context of a chronic financial crisis at the INSS, the laboral/común divide has become an austerity measure, a way of exercising sovereign power to filter away the human and economic “wastes” of a bloated state.  Writing about the quest for access to scarce antiretrovirals during West Africa’s AIDS epidemic, Vinh-Kim Nguyen (2010) labels this kind of filtration “triage.” As the need for long-term kidney care among the poor and marginalized in Nicaragua and elsewhere grows, decisions about how (and indeed whether) the kidney’s lost filtration capacity will be compensated by money and dialysis machines constitute a volumetric variation of what Nguyen calls “therapeutic sovereignty” (see also Melo 2017).

A declaration of CKDnt as laboral mobilizes benefits based on a view of the disease as equivalent to an occupational injury. This makes sense to CKDnt patients, who believe there is a connection between the volumetric dysfunction in their kidneys and a volumetric dysfunction in the plantation landscape. Many reckon that the epidemic must have to do with the excessive volume of pesticide residues in the air they breathe and water they drink.

Research has yet to verify the theory that CKDnt is caused by toxic exposure. Epidemiologists have suggested other environmental connections and volumetric dysfunctions. Cañeros, it seems, aren’t able to drink enough water (contaminated or clean) while on the job. The demand by field managers for quick disposition of tareas combines with the intense Central American heat (Nading 2016) to produce a generalized state of dehydration (Glaser, et al 2016), which can compromise kidney function. According to some studies, the simple UV filtration provided by 15 minutes per hour under shade tents could alleviate this problem.

Cañeros and their families continue asking sugar companies and scientists to not only help them access pensions and dialysis, but also filter good air from bad, safe water from contaminated water, ultraviolet light from skin. They are not alone. As extreme heat and toxicity become globally normalized, filtration presents itself as a key biopolitical technique, addressing the question of who will be exposed, and who will be protected.


Glaser, J., et al. (2016) Climate change and the emergent epidemic of CKD from heat stress in rural communities: The case for heat stress nephropathy. Clinical Journal of American Society of Nephrology 11(8) 1472-1483.
Melo, M (2017) Stratified access: Seeking dialysis care in the borderlands. In: MulliganJ and Castañeda, H (eds.) Unequal Coverage: The Experience of Health Care Reform in the United States. New York: NYU Press, pp. 59-78.
Nading, Alex. 2018. Dams and dialysis. Theorizing the Contemporary, Cultural Anthropology website, July 26, 2018. Available here
Nading, Alex. 2016. Heat. Theorizing the Contemporary, Cultural Anthropology website, April 6, 2016.
Nguyen, VK (2010) The Republic of Therapy: Triage and Sovereignty in Africa’s Time of AIDS. Durham: Duke University Press.