Clinical relevance of marginal low Protein S

P. Lodemann1, D. Peetz1, T. Held1, W. Ludwig1, J. Oldenburg2 (1Berlin, Germany, 2Bonn, Germany)

Venous thrombosis
Date: 17.02.2017,
Time: 17:15 - 18:15

Objective: The laboratory diagnosis of Protein S deficiency is challenging not only due to the fact that Protein S is bound to C4BP but also because there are heterogeneous assays that can be performed. Furthermore, the differentiation into the classical three types of Protein S deficiency is not always as simple as it looks like. We like to discuss the current algorithms of Protein S testing along with presentation of a case, thereby questioning how clinically relevant are marginal low Protein S values.

Methods: We present a case with the c.1501T>C Mutation in the protein S Gene and discuss current algorithms for Protein S deficiency in the context of marginal low cases.

Results: The finding of a marginal low Protein S should be interpreted with caution. Repeated measurements are mandatory to establish a diagnosis. Genetic testing may be helpful in interpreting the data, and find a potential cause, especially if combined with family analysis, but for many mutations derived from one or few cases, clinical data is limited and the causative role has to be scrutinized.

Conclusion: In patients with only marginal low Protein S values, it is difficult to judge whether and to what extend the patient has a thrombophilic diathesis even if the underlying genetic cause can be identified. Interpretations should be made with caution, and balanced with the individual clinical history including the family history if accessible.