Victoria Wasteney was treated 'reasonably' by her employer, East London NHS Trust, an Employment Tribunal has ruled.
She was accused of "harassing and bullying" her Muslim colleague for giving her a book about a Muslim woman's encounter with Christianity.
An internal disciplinary panel in February 2014 found her guilty of three charges of misconduct related to the accusations of "bullying and harassment" - praying with her colleague, giving her the book and inviting her to church events.
Miss Wasteney was suspended for nine months and had to accept a range of rulings designed to stop her discussing her faith and beliefs with colleagues.
She had argued she had been discriminated against because of her faith but a judge rejected that.
After the decision she said: "I conducted all my conversations with my colleague in a sensitive and appropriate way.
"I knew she was from a different faith background and I was respectful of that. I didn't force my beliefs on anyone at any point. Surely there should be room for mutual conversations about faith, where appropriate, in the workplace?
"I am extremely disappointed with the Tribunal's decision to side with my employer. There is already an unnatural caginess around faith and belief which is an obstruction to building meaningful relationships in the workplace.
"This decision will only perpetuate that, to the detriment of working relationships in the NHS."
Miss Wasteney was supported by the Christian Legal Centre.
Chief Executive, Andrea Williams, said: "Victoria has been punished and left out in the cold for being honest and open about her faith.
"The way she has been treated will only lead others to keep a low profile when it comes to faith and belief in the workplace.
"Are these the kind of workplaces we want, where people are forced to hide their identity and the things that matter most to them? Such an environment is detrimental to meaningful working relationships and ultimately to productivity.
"With the general election fast approaching, what will political parties do about the place of Christianity in the workplace, particularly in the NHS?
"The current 'equality and diversity' framework is having the opposite effect to what was intended. It is driving different people apart, not bringing them together, by breeding an atmosphere of mistrust in which people constantly feel as if they are walking on eggshells.
"Victoria's case clearly demonstrates this. What will our politicians do to restore trust in the workplace?"
East London NHS Trust was unable to give a statement.