No. Modern laboratory instruments can detect lead at concentrations substantially below the regulatory threshold for lead-based paint.
For example, a laboratory might report 500 ppm, 1,500 ppm, or 3,000 ppm of lead. Lead is clearly present, but those concentrations are below the California lead-based-paint threshold of 0.5% by weight, or 5,000 ppm.
That distinction can be important when interpreting a report.
However, detectable lead may still be relevant when paint will be sanded, demolished, or otherwise disturbed. Worker-protection, waste-disposal, and other requirements should be evaluated separately rather than assuming that paint below 5,000 ppm presents no regulatory considerations.