Adjusted calciumCorrected calcium
Blood calcium recalculated for your albumin level, so a low protein does not look like low calcium.
About half the calcium in blood is bound to albumin and is not biologically active; the rest is free and does the work. A total calcium measurement counts both, so when albumin is low the total falls even though the active portion is unchanged.
It matters because that arithmetic artefact is common. Adjusted calcium applies a correction based on the measured albumin, which is why it is usually the figure clinicians read when albumin is abnormal.
In practice the correction is an approximation rather than a measurement, and where the answer really matters an ionised calcium test measures the free portion directly.