Vitamin A Deficiency Workup

Updated: Oct 12, 2016
  • Author: George Ansstas, MD; Chief Editor: George T Griffing, MD  more...
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Workup

Laboratory Studies

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  • A serum retinol study is a costly but direct measure using high-performance liquid chromatography. A value of less than 0.7 mg/L in children younger than 12 years is considered low. [21]
  • A serum RBP study is easier to perform and less expensive than a serum retinol study, because RBP is a protein and can be detected by an immunologic assay. RBP is also a more stable compound than retinol with respect to light and temperature. However, RBP levels are less accurate, because they are affected by serum protein concentrations and because types of RBP cannot be differentiated. [22, 23, 24]
  • The serum retinol level may be low during infection because of a transient decrease in the RBP.
  • A zinc level is useful because zinc deficiency interferes with RBP production.
  • An iron panel is useful because iron deficiency can affect the metabolism of vitamin A.
  • Albumin levels are indirect measures of vitamin A levels.
  • Obtain a complete blood count (CBC) with differential if anemia, infection, or sepsis is a possibility.
  • An electrolyte evaluation and liver function studies should be performed to evaluate for nutritional and volume status.
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Imaging Studies

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  • In children, radiographic films of the long bones may be useful when an evaluation is being made for bone growth and for excessive deposition of periosteal bone.
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Procedures

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  • Dark-adaptation threshold should be tested. [25]
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