Laboratory Assessment for Children Suspected of Malnutrition

Core Laboratory Tests

For children suspected of malnutrition, a comprehensive laboratory assessment should include routine electrolytes, minerals, triglycerides, serum urea, hemoglobin, total lymphocyte count, and proteins with shorter half-life such as pre-albumin or retinol-binding protein 1, 2, 3
Electrolytes, including sodium, potassium, and chloride, should be assessed in children suspected of malnutrition 1, 3
Minerals such as calcium, phosphorus, and magnesium should be evaluated in children suspected of malnutrition 1, 3
Triglycerides should be measured in children suspected of malnutrition 1, 3
Serum urea should be assessed in children suspected of malnutrition 1, 3
Hemoglobin and total lymphocyte count should be evaluated to assess protein status in children suspected of malnutrition 1, 3
Pre-albumin and retinol-binding protein, which have shorter half-lives, can better reflect improving nutritional status and recent nutritional changes in children suspected of malnutrition 1, 3

For severe malnutrition, additional tests such as nitrogen excretion and nitrogen balance should be considered 1, 3
Plasma amino acid profile can help characterize protein deficit in children with severe malnutrition 3
Serum vitamin concentrations and trace element concentrations should be assessed in children with long-term malnutrition 3

Mid-upper arm circumference (MUAC) is particularly valuable when weight is unreliable due to edema, and can be used to assess moderate malnutrition 1, 2, 3, 5
Weight-for-age or weight-for-height z-score measurement can be used to assess malnutrition in children 5, 6

In severe acute malnutrition, pharmacokinetics of medications may be altered, with lower clearance for medicines metabolized in the liver 7
When evaluating weight changes, assessment of fluid intake and output should accompany weight measurements to determine if weight changes are due to fluid shifts or actual tissue changes 1, 2, 3
For children with severe malnutrition receiving antibiotics, medication dosing may need adjustment 7

Relying solely on albumin as a marker of malnutrition, as it can be affected by inflammation and protein redistribution 1, 3
Failing to account for fluid status when interpreting weight changes 1, 2, 3
Not repeating measurements frequently enough in critically ill or rapidly changing patients 3
Overlooking the need for vitamin and trace element assessment in long-term cases 3
Interpreting isolated laboratory values without considering the clinical context and anthropometric measurements 6