Health Secretary Nicola Sturgeon told MSPs she is "shocked and extremely angry" at a report into manipulation of waiting times by NHS Lothian, on 21 March 2012.
Ms Sturgeon had commissioned an external review of NHS Lothian's waiting times management following reports last year NHS Lothian were offering patients treatment in England at shot notice and subsequently recording them as unavailable if they did not travel.
The health secretary said the key finding of the PWC report - which examined the period from April to December 2011 - was that NHS Lothian had been applying periods of unavailability to some patients inappropriately in order to artificially reduce the numbers of patients who would be otherwise have been reported as breaching waiting times guarantees.
NHS Lothian had already instigated disciplinary proceedings, Ms Sturgeon confirmed.
She said this practice was "completely unacceptable" and said the report had found management culture in NHS Lothian contributed to this situation.
The health secretary said she had instructed the chair of NHS Lothian to carry out an investigation into the extent of such a culture in NHS Lothian and what needed to be done about it.
Ms Sturgeon said she had taken steps to assure herself that all other health boards in Scotland were acting in line with the waiting times guidance.
She has also called for a specific and detailed audit to be carried out into local waiting times management and process as part of each each health board's internal audit programme over 2012/13.
Scottish Labour health spokesperson Jackie Baillie said she too was shocked and angry that the "figures had been fiddled" and called for a Scotland wide inquiry and a full and thorough review by Audit Scotland of every health boar in Scotland.
Speaking for the Scottish Conservatives, David McLetchie said: "There was no getting away from fact NHS Lothian at certain levels showed more concern about the doctoring of statistics than the treatment of patients.
He asked if an independent investigation under the health secretary might not be the way to ensure there was the confidence that "the heads that should roll will roll".