Review Question - QID 109823

A 27-year-old African American man presents to a primary care physician for a routine checkup as a new patient. The patient states that he has been doing well lately and recently was promoted at his job. He states that 2 weeks ago he went to the ED for severe pain and was treated with morphine and oral fluids and discharged home that night. This had happened once before and he was treated similarly. The patient states that he drinks 7 to 8 alcoholic beverages per night and smokes 1 pack of cigarettes per day. The patient states that he has been gaining weight recently due to a diet consisting mostly of fast food. His temperature is 98.6°F (37°C), blood pressure is 118/74 mmHg, pulse is 102/min, and respirations are 12/min. Physical exam is unremarkable. Basic labs are ordered as seen below.

Hemoglobin: 8 g/dL
Hematocrit: 28%
Mean corpuscular volume: 72 um^3
Leukocyte count: 6,500/mm^3 with normal differential
Platelet count: 157,000/mm^3

Serum:
Na+: 139 mEq/L
Cl-: 100 mEq/L
K+: 4.3 mEq/L
HCO3-: 25 mEq/L
BUN: 20 mg/dL
Glucose: 99 mg/dL
Creatinine: 1.1 mg/dL
LDH: 540 U/L
Ca2+: 10.2 mg/dL
AST: 12 U/L
ALT: 10 U/L

Which of the following is the most likely reason for this patient's laboratory abnormalities?