A Transgender Man Being Evaluated for a Kidney Transplant

Summary

DOI: 10.1373/clinchem.2016.268839

Student Discussion

Cameron T. Whitley¹ and Dina N. Greene^2*

¹Department of Sociology, Michigan State University, East Lansing, MI; ²Department of Laboratory Medicine, University of Washington, Seattle, Washington.
*Address correspondence to this author at: Department of Laboratory Medicine, University of Washington, Campus Box 357110, Seattle, Washington 98195-7110. Fax 510 –5595306; e-mail [email protected]

Case Description

A 33-year-old female-to-male transgender individual (height, 5’1”; weight, 135 lb) presented to emergency care with acute otitis media and hypertension (170/110). Currently prescribed medications include daily atorvastatin and intramuscular testosterone cypionate injections (100 mg/week). The patient refused admission because of discrimination concerns as a transgender man, but presented to his primary care physician the following morning. Laboratory results revealed a urine total protein concentration of 199.5 mg/dL (random collection, 0.0–10.0 mg/dL) and an estimated glomerular filtration rate (eGFR)3 of 31 mL/min/1.73m2 if assessed using the male equation or 23 mL/min/1.73m2 if assessed using the female equation. On the basis of male categorization, the patient was diagnosed with stage 3 chronic kidney disease (CKD3), prescribed carvedilol, and strongly encouraged to discontinue testosterone, to which he agreed. The patient transferred to an alternate institution; here testosterone administration was restarted, lisinopril was prescribed, and reduction in protein and sodium intake was encouraged. Incidentally, the patient had maintained a vegan diet for >10 years.

Renal transplant evaluation was initiated several months later. Corresponding male eGFR was 24 mL/min/1.73m2, but the corresponding female eGFR was 18 mL/min/1.73m2. Urine protein excretion was 3 g/day. Because transplant candidates require a GFR <20 mL/min/1.73m2 (1) and because the patient’s male-calculated eGFR was above the cutoff, he was not listed. An evaluation 4 months later documented an eGFR of 21 and 15 mL/min/1.73m2 for corresponding male and female levels, respectively. In the patient’s medical chart, only the corresponding male eGFR was documented, and the medical care team did not consider that the sex-based equations will lead to a different interpretation. All eGFR values were calculated using the Modification of Diet in Renal Disease study equation.

Reference

University of Pennsylvania. https://www.pennmedicine.org/~/media/documents%20and%20audio/patient%20guides%20and%20instructions/transplant/kidney_transplant_selection_criteria.ashx?la=en (Accessed October 2016).

Questions to Consider

What genetic, biological, and environmental factors can influence creatinine concentration and lead to subsequent uncertainty in the eGFR interpretation?
Does exogenous testosterone administration influence kidney function?
What other laboratory results may be difficult to interpret in transgender patients?

Final Publication and Comments

The final published version with discussion and comments from the experts appears in the November 2017 issue of Clinical Chemistry, approximately 3-4 weeks after the Student Discussion is posted.

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