The biggest test yet for 'Trumpcare' could come on Monday - here's what to look for

The American Health Care Act, the Republican bill to overhaul the US healthcare system, could face a serious test as early as Monday.

The Congressional Budget Office is expected to release its score for the GOP's legislation to repeal and replace the Affordable Care Act, also known as Obamacare, to determine the budgetary and coverage impact of the new AHCA.

The CBO score will help estimate the long-term effects of the AHCA compared to their baseline estimates under the ACA, typically looking at the effects over a 10-year time horizon.

While Republican leaders have cast doubts on the importance of the CBO score, the nonpartisan office was the most accurate predictor of the effects of the ACA.

Here are some key details to look out for in the CBO report:

• The change in the number of people with health insurance: The highlight of the report will most likely be the CBO's estimate of the number of people that will gain or lose coverage from the AHCA. The most likely adjustments will be due to the changes to the structure of tax credits for people to buy insurance under the new law and its changes in funding for Medicaid expansion. S&P estimated 6 to 10 million people will lose coverage under the AHCA, while the Brookings Institution projected up to 15 million.
• The impact on the federal deficit: One of the complaints of conservative Republicans positioning themselves against the AHCA is that the tax credits and other funding, combined with the repeal of Obamacare's taxes, will cause the federal deficit to increase. The CBO score will estimate the effects of the AHCA
• Cost of premiums: The second-most expensive silver-level plan was used by the CBO to project premium growth under the ACA. In fact, despite large jumps over the past year, average premiums for 2017 are roughly in line with the CBO's original projections. How the average cost of insurance changes under the new law will be another major sticking point for opponents of the AHCA.

The CBO score is not a perfect indicator - changes to the legislation as it goes through various committees, as well as legal challenges, can roil its estimates. It does, however, give a look at how the current iteration of the law will change the insurance industry and healthcare for Americans.