In trans persons on gender-affirming hormonal treatment, a decrease (in trans women) or increase (in trans men) in hematocrit is often observed. Reference ranges for evaluation of hematocrit levels in trans persons have not been established. This prospective cohort study is part of the European Network for the Investigation of Gender Incongruence (ENIGI). At the Ghent and Amsterdam sites, we included 625 hormone-naïve trans persons. Gender-affirming hormonal treatment was initiated at the first visit. In trans men, serum hematocrit (Hct) levels increased during the first year (+4.9 Hct %, 95% CI 3.82-5.25), with the most pronounced increase during the first 3 months (+2.7 Hct %, 95% CI 1.94-3.29). Trans men receiving testosterone esters had a larger increase in serum hematocrit levels compared to trans men receiving testosterone undecanoate (Δ 0.8 Hct %). Of 192 trans men, 22 (11.5%) developed serum hematocrit levels ≥50.0%. Trans men on testosterone undecanoate were less likely to develop hematocrit levels ≥50% or ≥52%, compared to trans men on testosterone esters, and were less likely to develop hematocrit levels ≥50%, compared to trans men on testosterone gel. In trans women, serum hematocrit had dropped by 4.1 Hct % (95% CI 3.50-4.37) after 3 months, after which only small decreases were observed. In conclusion, serum hematocrit levels can be found in the reference range of the perceived gender as from 3 months after the initiation of gender-affirming hormonal treatment.

We present a case of a 52-year-old woman of Ghanaian origin who developed Plasmodium falciparum malaria 4 years after leaving Africa. She had not returned to an endemic area since. We hypothesize several possible scenarios to explain this infection, of which we believe recrudescence of P. falciparum is the most plausible. This occurred most likely as a consequence of waning immunity several years after leaving a high-transmission area. She recovered after a 3-day treatment with atovaquone/proguanil.

We report the case of a patient on chronic hemodialysis treatment with paroxysms of severe arterial hypertension accompanied by tachycardia, pallor, sweating and tremor. Measurement of plasma catecholamines revealed norepinephrine level of 4625 pg/mL (reference range 191-225 pg/mL), epinephrine level of 1035 pg/mL (58-76 pg/mL) and dopamine level of 148 pg/mL (50-100 pg/mL). MRI showed a left adrenal mass of 2 cm. After the patient was started on an alpha-1 adrenergic receptor blocker, she underwent a left adrenalectomy. Anatomopathological examination confirmed the diagnosis of pheochromocytoma. Although urinary testing is not possible in anuric hemodialysis patients, diagnosis of pheochromocytoma can be made through measurement of plasma free metanephrines and/or plasma catecholamines.