Diagnostic Test

A method of increasing the sensitivity of a diagnostic test for diagnosing Mycobacterium tuberculosis infection in a human, wherein said diagnostic test comprises contacting T cells from said human with a Mycobacterium tuberculosis antigen which is not Rv3879c, said method additionally comprising

• (i) contacting T-cells from said human with one or more of
• (a) a peptide having the sequence shown in SEQ ID NO:
• 1;
• (b) a peptide having or comprising the sequence of at least 8 consecutive amino acids of the sequence shown in SEQ ID NO:
• 1;
• or
• (c) a peptide having or comprising a sequence which is capable of binding to a T-cell receptor which recognises a peptide as defined in (a) or (b);
• and
• (ii) determining whether any of the said T-cells recognise said peptide,
• wherein steps (i) and (ii) are optionally carried out in vitro.