What causes pseudothrombocytopenia (false low platelet count)?

From the Guidelines

Pseudo hyperplatelet, also known as pseudothrombocytosis, is most commonly caused by the presence of small platelet aggregates or clumps in the blood sample, which can lead to falsely elevated platelet counts. This condition can be caused by various factors, including:

• Hemolysis during blood drawing, especially with small-gauge needles or excessive vacuum pressure 1
• Prolonged tourniquet application, which can cause platelet activation and aggregation
• Excessive fist clenching during collection, leading to platelet activation and clumping
• Delayed sample processing, allowing platelets to aggregate and form clumps
• Extreme thrombocytosis (platelet count >1,000/μL), which can increase the likelihood of platelet clumping
• Severe leukocytosis (white blood cell count >100,000/μL), which can also contribute to platelet clumping
• Cold storage of samples, which can cause platelet activation and aggregation To avoid pseudothrombocytosis, it is essential to use appropriate collection techniques with minimal trauma, avoid excessive tourniquet time, process samples promptly, and consider collecting blood in lithium heparin tubes rather than serum tubes when thrombocytosis or leukocytosis is present 1. If pseudothrombocytosis is suspected, comparing platelet counts with different sample processing methods or using alternative tests, such as flow cytometry, can help confirm the diagnosis and prevent unnecessary and potentially harmful treatment for thrombocytosis. Some key points to consider when evaluating pseudothrombocytosis include:
• The clinical presentation and medical history of the patient
• The laboratory results, including platelet counts and other blood cell parameters
• The potential causes of pseudothrombocytosis, such as hemolysis or platelet clumping
• The appropriate collection and processing techniques to avoid pseudothrombocytosis
• The use of alternative tests or methods to confirm the diagnosis and rule out other conditions.

From the Research

Causes of Pseudo Hyperparathyroidism

• The provided studies do not directly address the causes of pseudo hyperparathyroidism, but rather focus on secondary hyperparathyroidism (SHP) in the context of chronic kidney disease (CKD) 2, 3, 4, 5, 6.
• However, it can be inferred that abnormalities in mineral metabolism, such as hypocalcemia and hyperphosphatemia, can contribute to the development of SHP, which may be related to pseudo hyperparathyroidism 2, 4.
• Vitamin D deficiency, particularly 1,25-dihydroxyvitamin D (1,25[OH]2D) deficiency, is also a key factor in the development of SHP, and may be relevant to pseudo hyperparathyroidism 3, 6.
• Other factors, such as downregulation of parathyroid vitamin D and calcium-sensing receptors, and increased fibroblast growth factor 23 (FGF-23) concentration, may also play a role in the development of SHP and potentially pseudo hyperparathyroidism 4.

Related Conditions

• Chronic kidney disease (CKD) is a major risk factor for the development of SHP, and may be related to pseudo hyperparathyroidism 2, 3, 4, 5, 6.
• Vitamin D deficiency and insufficiency are common in patients with CKD, and may contribute to the development of SHP and potentially pseudo hyperparathyroidism 3, 5, 6.
• Abnormalities in mineral metabolism, such as hypocalcemia and hyperphosphatemia, can contribute to the development of SHP, and may be related to pseudo hyperparathyroidism 2, 4.