A doctors' organisation believes vacancy rates for consultants are being underestimated in official figures, cutting them by more than half.
Official figures show NHS Scotland staff numbers have increased slightly in a year but while vacancy rates for medical and dental consultants have fallen, those for nurses and midwives have risen to more than 2,400.
The September 30 census found 5,357.5 whole-time equivalent (WTE) medical and dental consultants in post, up 3.2% on the previous year, while vacancy rates for these positions fell by 8.7% to 393.1 (6.8%) – the lowest level since December 2016.
More than two thirds (65%) had been lying empty for six months more.
However, BMA Scotland argues the true vacancy rate for the roles is likely to be around 13.9% as the method of counting excludes what it believes to be around 375 vacancies.
The organisation's Dr Simon Barker said: "This analysis shows that by not including certain categories of vacancy, the official statistics simply don't provide the full picture of the scale of consultant vacancies in our NHS.
"For example, vacant posts that go unfilled are then removed from official figures," he added.
"Collectively, that means there are potentially around 375 vacancies on top of those counted by official figures – the equivalent of a large hospital empty of its senior doctors."
The Chair of our Consultants Committee today commented on FOI data which shows the true scale of consultant vacancies in Scotland's NHS is likely to be much higher than reported in official figures. We are clear that this must be addressed. More here:https://t.co/QrYiQ6rU5t
— BMA Scotland (@BMAScotland) December 4, 2018
Overall, 162,945 staff were directly employed by NHS Scotland last year, up 0.2% from the previous year, a rise for the seventh year in a row but a slowdown in the growth rate.
The picture across Scotland's health board varies, with six out of 14 reporting a decrease in staff at the September 30 census point compared to the same date in 2017.
The number of qualified midwifery and nursing staff in post was 43,267.5 WTE, up 15.7% year on year, but there were variations across the country with eight boards reporting falling numbers.
Vacancy rates for these roles also increased to 2,401.1 WTE, up from 4.8% to 5.3%, just over a third (36%) had not been filled for three months or longer.
The student intake for nursing and midwifery in 2017/18 rose to the highest for seven years at 3,471, up 6.3% on the previous year.
Sickness absence rates across Scotland's health boards have risen to their highest figure in a decade at 5.39%, up from 5.20% in 2016/17.
The Royal College of Nursing said the figures show the need to "enshrine safe staffing in law".
Scottish Liberal Democrat health spokesman Alex Cole-Hamilton said the apparent extent of hidden consultant vacancies is "staggering" and called for the Scottish Government to tackle empty posts.
He added: "There's no way the Scottish Government can take effective action to counter shortages if they're working off wildly wrong numbers."
His Green counterpart, Alison Johnstone, said: "It's vital that Ministers now issue updated guidance to health boards so we get an accurate picture of the staffing gap and can respond accordingly."
Scottish Labour's health spokeswoman Monica Lennon accused the Scottish Government of having "failed to properly plan the workforce and support existing staff".
Health Secretary Jeane Freeman said the number of consultants, medical and dental staff are at a "record high" and around 2,600 nursing and midwifery training places would be created by 2021 as part of measures to boost the supply of these staff.
She added: "Under this government the number of qualified whole time equivalent nurses and midwives has increased by 5.5% and consultants have risen by 50.8%.
"The vacancy rates for consultants, nursing and midwifery and allied health professionals have all reduced over the last quarter."