A nurse is caring for a patient who has a body mass index (BMI) of 18. The nurse should place the patient in which of the following BMI categories?

Choice A rationale

The normal range for thyroxine (T4) is typically 5.0 to 11.0 mcg/dL. A value of 9.2 mcg/dL falls within this normal range, indicating euthyroid function. T4 is a thyroid hormone that regulates metabolism and is not a direct indicator of a nutritional deficit, so this finding would not be reported as abnormal. This level reflects normal metabolic status.

Choice B rationale

Albumin is a protein produced by the liver and is a key indicator of nutritional status. The normal range for albumin is 3.5 to 5.0 g/dL. A value of 2.1 g/dL is significantly low and indicates severe protein-calorie malnutrition. Low albumin can lead to third-spacing of fluids and edema and is a critical finding that must be reported to the provider.

Choice C rationale

The normal white blood cell count (WBC) range is 4,500 to 11,000 cells/mm. A WBC of 6,000/mm is within this normal range. The WBC count indicates the body's immune response and is not a primary marker for nutritional status. This level does not suggest infection or an inflammatory process requiring immediate reporting.

Choice D rationale

The normal sodium range is 135 to 145 mEq/L. A sodium level of 139 mEq/L is within the normal range. Sodium is a critical electrolyte for fluid balance and nerve function, but this value is not indicative of an electrolyte imbalance or a nutritional problem that requires immediate reporting to the provider.

Choice A rationale

Obesity is defined as a BMI of 30 or greater. A BMI of 18 is significantly below this threshold. This category indicates a high level of body fat, which increases the risk for various chronic diseases such as heart disease, type 2 diabetes, and certain cancers. The patient's BMI does not fit this classification.

Choice B rationale

Overweight is defined as a BMI between 25.0 and 29.9. The patient's BMI of 18 is substantially below this range. This category indicates excess body weight relative to height but is not classified as obese. Individuals in this category are at an increased risk for health problems.

Choice C rationale

Underweight is defined as a BMI below 18.5. The patient's BMI of 18 falls directly into this category. Being underweight can be a sign of malnutrition or an underlying health issue and can lead to its own set of health problems, including weakened immune system, osteoporosis, and anemia.

Choice D rationale

Healthy weight is defined as a BMI between 18.5 and 24.9. The patient's BMI of 18 is just below this range. This category is associated with the lowest risk for weight-related health issues and is considered the standard for good health. The patient's BMI is not within this range.