Final answer:
The blood test that assesses kidney function is Blood Urea Nitrogen (BUN), which provides an estimate of urea levels in the blood, indicating renal health.
Step-by-step explanation:
A blood test that analyzes the ability of the kidneys to perform their function is the Blood Urea Nitrogen (BUN). The BUN test estimates the urea levels in the blood, which serves as an important indicator of kidney function. An abnormal BUN level may suggest impaired kidney function or disease. Blood tests, including the measurement of plasma creatinine alongside BUN, help assess renal functions effectively. While other tests such as albumin levels, fasting blood sugar (FBS), and glucose tolerance tests (GTT) are useful for different diagnostic purposes, the BUN is specifically important for evaluating kidney health.