Should label elements exclude formatting for screen-readers

Question

Does including formatting within a <label> element have any positive or negative effect on screen readers (or any other disability support equipment)?

For example, would either of the following cause issues?

<label for="txtName"><b>Name:</b></label> <input type="text" id="txtName"/>

<label><b>Name:</b> <input type="text" id="txtName"/></label> 

Or should it be...

<b><label for="txtName">Name:</label></b> <input type="text" id="txtName"/>

<b><label>Name: <input type="text" id="txtName"/></label></b>

Does it make any difference?

Answer 1

No, this doesn't affect screen readers in any way. Screen readers ignore attributes such as bold by default, but they can be set to speak and/or indicate them in Braille.