Bitcoin bulls have one price level to defend

Losing it is one of three warning signs she's watching. "A deeper correction would become more likely if ETF flows turn negative for several sessions, the 10-year Treasury yield continues to rise and support below $82,000 fails," she said.

ETF flows track money moving in and out of U.S. exchange-traded funds that hold bitcoin. Steady outflows would signal that big investors are pulling back.

Iliya Kalchev, an analyst at Nexo Dispatch, drew his line a little lower. "A sustained break below $80,000 would suggest the market isn't ready to push higher for some time," he said.

A bounce could still flip the picture. "Renewed momentum from here could carry price well above $90,000," Kalchev said.

The next test may come from the economy rather than the charts. Anderson said the Personal Consumption Expenditures index, the Federal Reserve's preferred inflation gauge, "will be the market's next guidance" on how long inflation is likely to stay high.