9.7: Pyruvate Kinase (PK) Deficiency

A Laboratory Guide to Clinical Hematology · LibreTexts

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    Normal PK Function:

    Pyruvate Kinase catalyzes the conversion of phosphoenolpyruvate to pyruvate which results in the production of ATP from ADP. A lack of pyruvate kinase results in the ability of cells to maintain proper cell shape, normal lifespan, and low levels of 2,3-PBG.1,2

    Mutation:1,2

    Mutations in the PKLR gene leading to decreased levels of pyruvate kinase.

    Inheritance:1,2

    Autosomal recessive

    Complications:1,2

    Chronic hemolytic anemia

    Splenomegaly

    Jaundice

    Gallstones

    Notes:1

    WBCs contain more pyruvate kinase than RBCs.

    Laboratory Results for PK Deficiency:1

    CBC:

    Hb: Decreased

    RETIC: Increased

    *Note: The term “pyknocyte” is not universally used. It refers to a small, dehydrated, dark-colored RBC.

    PBS:

    Normocytic

    Normochromic

    Echinocytes

    Pyknocytes*

    Post-splenectomy shows varying degrees of anisocytosis and poikilocytosis

    Other Tests:

    Osmotic Fragility: Normal

    Pyruvate Kinase Assay: Decreased

    Indirect bilirubin: Increased

    LDH: Increased

    Haptoglobin: Decreased or absent

    References:

    1. Lake M, Bessmer D. Hemolytic anemia: enzyme deficiencies. In: Clinical laboratory hematology. 3rd ed. New Jersey: Pearson; 2015. p. 334-47.

    2. Keohane EM. Intrinsic defects leading to increased erythrocyte destruction. In: Rodak’s hematology clinical applications and principles. 5th ed. St. Louis, Missouri: Saunders; 2015. p. 367–93.

    This page titled 9.7: Pyruvate Kinase (PK) Deficiency was last modified on Fri, 11 Sep 2026 16:40:06 GMT and is shared under a CC BY-NC 4.0 license and was authored, remixed, and/or curated by Valentin Villatoro and Michelle To (Open Education Alberta) via source content that was edited to the style and standards of the LibreTexts platform.