More than a quarter of calls to NHS 24 were abandoned over the winter, new figures have shown.
The section of the health service operates the 111 non-emergency number, which operates as an out-of-hours service.
Health services in Scotland have been overstretched in recent months, with the Scottish Government forced to bring in the military to support struggling ambulance services.
In addition, health boards have urged people to turn to NHS 24 instead of attending overcrowded emergency departments.
Between October 1 and January 16, 163,814 calls to the helpline were abandoned out of a total of 632,637 – some 25.8% – according to data provided to Scottish Labour under freedom of information legislation.
A similar request submitted by the Scottish Conservatives found 68,119 calls were abandoned in September of last year, more than any of the following four months.
On December 27, one person waited two hours and 14 minutes before the call was abandoned.
The longest wait for a call to be answered took place on January 16, when someone waited two hours and 21 minutes.
The average waiting time throughout the entire period covered is 18 minutes and 42 seconds.
Scottish Labour deputy leader Jackie Baillie called on the Scottish Government to better support NHS 24.
“These damning statistics are clear – the SNP’s failure to support NHS 24 has led to thousands of Scots missing out on medical help,” she said.
“Throughout the winter, A&E services, NHS 24 and ambulance services have been in crisis but (health secretary) Humza Yousaf has looked the other way.
“Staff have worked tirelessly, but with thousands of Scots in need being left hanging on the telephone it is clear that greater support is needed.
“This is unacceptable. Lives are being lost now because of the SNP’s failure to support NHS staff.
“Winter is far from over – Humza Yousaf must stop turning his back on the staff of our NHS and those in need and act to support services.”
Scottish Tory health spokesman Dr Sandesh Gulhane described the number of abandoned calls as “astonishing and deeply concerning”.
He added: “Patients have been encouraged to use NHS 24 as a first port of call before going to Scotland’s desperately over-stretched A&E wards, so some of these calls will relate to serious conditions.
“This has created another dangerous bottleneck in our NHS, which is at absolute breaking point under the SNP. Potentially life-threatening incidents are likely to have been missed as a result of so many calls not being connected.
“Humza Yousaf has completely failed to step up and give NHS 24 the resources they need. All too often he is taking his eye off the ball and only reacting when it is too late.
“These figures must act as a catalyst for the SNP’s health secretary to urgently outline a plan that will guarantee patients can be confident their calls to NHS 24 will be answered at all times.”
A spokeswoman for NHS 24 said: “The winter period is busy for the whole NHS across Scotland and this year was particularly busy due to the Covid-19 pandemic and the Omicron variant. Patients calling with Covid-19 symptoms accounted for approximately 20–25% of calls to 111 during this period.
“In addition to the increase in demand due to Covid, NHS 24’s 111 service was required to rapidly move to from a predominantly out-of-hours service to a 24/7 operation. There has been a 45–50% increase in calls to NHS 24 since early 2020.
“This unprecedented growth in demand for the 111 service means that, at times, people have experienced a longer wait time for their calls to be answered.
“Our automated telephone messaging system gives callers options of alternative routes to safe and effective care at the start of the call, which may be better aligned to their individual needs. This clear signposting means people may choose to end their call to 111.
“For example, in the case of an emergency, callers will always be advised to dial 999. Someone calling for information about the Omicron variant may choose to hang up and dial the Covid information line.
“We also advise people that they may be able to get help from their local community pharmacy, or via our symptom checkers on NHSinform.scot which saw a significant increase (140%) in visitors during the period highlighted.”
In response to increasing demand, NHS 24 employed 422 new members of staff and opened three additional centres, the spokeswoman added.