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NCT Number: NCT04478760

Trans & Non-binary Reference Intervals While on Hormone Therapy Study

This study will find out what the reference intervals are for common blood tests in transgender people taking hormone therapy.

Reference intervals help doctors interpret blood test results. They are expressed as two numbers, and most normal results fall between them. If a results fall outside of them, it may be because of a disease. Some blood tests are also affected by normal difference between people, such as age, sex or ethnicity. For these tests, different reference intervals are given for each group of people. Having accurate reference intervals benefits patients because it allows doctors to identify disease faster.

Transgender people have a gender identity which does not match their sex characteristics at birth. Gender identity is the feeling of being a gender, and sex is the biological aspects of growing up male or female. Transgender people may use hormone therapy to help change their appearance to fit their gender identity. This involves taking either oestrogen or testosterone.

For blood tests which are affected by sex, it is not clear what reference intervals should be used for transgender people who are on hormone therapy. This is because they have a mixture of male and female sex characteristics. Answering this question will allow doctors to identify disease in them faster.

The study will take place at cliniQ, at King's College Hospital, which provides health services to transgender people. It will recruit healthy transgender people who attend the clinic for blood tests to monitor their hormone therapy. Participants will fill out a questionnaire, give a urine sample, then have their appointment as normal. Extra tests will also be performed on their blood sample. The aim is to recruit 240 participants. Participant's tests results will then be used to calculate reference intervals.

The study is funded by Viapath Group LLP.

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Key information

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Caldecot Centre, King's College Hospital, 15-22 Caldecot Road

London, SE5 9RS, United Kingdom

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Transgender or nonbinary people.
  • Aged 18 or older.
  • Taking testosterone or oestrogen therapy.
  • For 12 months or more.
  • Having routine hormone therapy monitoring at the clinic.

Exclusion criteria

  • Unable to give informed consent (including participants who cannot communicate in English).
  • History of chronic liver disease, chronic kidney disease, diabetes, or severe cardiovascular disease (including myocardial infection, deep vein thrombosis, stroke and pulmonary embolism).
  • Blood test results that indicate severe disease.
  • Pregnant or within one year after childbirth.
  • Other conditions which could put participants at risk by participating, or which could influence the results of the study.

Treatment and study plan

Primary outcomes

  1. Reference interval for transgender patients on hormone therapy

    Time frame: 1 day

    Establish reference intervals for routine chemistry and immunoassay test for transgender people on hormone therapy. Establish separate reference intervals for people on masculinising and feminising therapy if they differ substantially.

Secondary outcomes

  1. Compare the reference intervals in patients taking different hormone therapy formulations.

    Time frame: 1 day

    Compare different hormone therapy formulations to establish whether there are clinically significant difference in their effects on reference intervals.

  2. Compare transgender reference intervals to the existing ones

    Time frame: 1 day

    Compare the reference values for transgender people on hormone therapy with the existing cisgender reference intervals to establish whether they are similar enough for the cisgender reference intervals to be used instead.

Sponsors and collaborators

Lead sponsor

King's College Hospital NHS Trust

Other

Registry information

Official study title

Reference Intervals for 27 Routine Chemistry and Immunoassay Tests in Transgender Adults on Stable Hormone Therapy

Acronym: TransRIHTS

Important dates

Study start
2021
Primary completion
2024
Study completion
2024
First posted
Jul 21, 2020
Registry last updated
Sep 3, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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