Interpretation of Common Laboratory Values Flashcards

Which of the following serum calcium levels in a dialysis patient would most urgently require immediate notification of the physician?

Answer: 11.9 mg/dL

A serum calcium of 11.9 mg/dL represents significant hypercalcemia in a dialysis patient. Hypercalcemia causes cardiac arrhythmias, neurological symptoms, and accelerated vascular calcification. The physician must be notified promptly to adjust calcium-containing binders, vitamin D analogues, or dialysate calcium concentration.

What does the albumin level in a dialysis patient primarily reflect?

Answer: Nutritional status and inflammation

Serum albumin primarily reflects nutritional status and the presence of inflammation (acute phase response). In dialysis patients, low albumin (<3.5 g/dL) is strongly associated with increased mortality and reflects either protein-calorie malnutrition, systemic inflammation, or both.

A dialysis patient's hemoglobin is 8.2 g/dL and the reticulocyte count is low. What is the most likely cause of this finding?

Answer: Decreased erythropoiesis due to inadequate ESA dose or functional iron deficiency

A low hemoglobin with a low reticulocyte count suggests the bone marrow is not producing sufficient red blood cells. In dialysis patients, this pattern most commonly indicates inadequate ESA dosing, functional iron deficiency (insufficient iron for erythropoiesis despite adequate stores), or pure red cell aplasia.

What is the significance of a BUN:creatinine ratio greater than 20:1 in a dialysis patient?

Answer: It suggests a catabolic state, gastrointestinal bleeding, or high dietary protein intake

A BUN:creatinine ratio >20:1 in a dialysis patient suggests either excessive protein catabolism, upper gastrointestinal bleeding (where blood protein is digested and absorbed as urea), or very high dietary protein intake—all of which disproportionately raise BUN relative to creatinine.

In a hemodialysis patient, which combination of laboratory findings is most consistent with iron deficiency anemia?

Answer: Low ferritin (<100 ng/mL), low TSAT (<20%), low hemoglobin, low MCV

Iron deficiency anemia is characterized by depleted iron stores (low ferritin), insufficient iron for transport to the marrow (low TSAT), reduced hemoglobin synthesis (low hemoglobin), and small red cells (low MCV—microcytic anemia) from inadequate hemoglobin to fill each cell.

A hemodialysis patient's pre-dialysis labs show sodium of 136 mEq/L, but the patient reports drinking 3 liters of fluid since their last treatment. How does this help interpret their fluid status?

Answer: The high fluid intake relative to sodium suggests dilutional hyponatremia is developing or the patient has significant interdialytic fluid gain

When a patient consumes a large fluid volume and serum sodium appears normal (or low), this suggests a dilutional process—excess water ingestion has diluted both sodium and other solutes. In dialysis patients, this pattern indicates significant interdialytic fluid gain requiring aggressive ultrafiltration and potentially dietary sodium and fluid counseling.