Context.TraceId Guid issue

Hi 

We are doing Request and Response logging via Middleware. We decided to use Context.TraceId for unique identifier based on one of the article series assuming that TraceId is similar to GUID. However in our local system, when we see TraceID we see some 7 to 9 alphanumeric string. Is something wrong? Isn't traceId similar to guid string? Can we rely on TraceId to uniquely log request and corresponding response?