Diagnosis of Polycythemia vera
[PRV-1 diagnostics]
This test is supported by the German health insurance companies.
For Patients with an elevated level of hematocrit and erythrocytosis of unknown genesis, the tentative diagnosis “Polycythemia vera" may apply. However, until recently medical diagnostics for a direct proof of Polycythemia vera were not available. The current PRV-1 test uses the extremely elevated expression of the prv-1 gene in granulocytes of the Polycythemia vera patients. This is the first reliable and simple method available for confirming the tentative diagnosis of Polycythemia vera.
What is required? Scientific Background How is the diagnosis performed?
What is required?
We need monovettes with a total of 40 ml EDTA-Blood which must not be cooled. Please send the specimens together with the necessary documentation (see below) to the following address:
Oncoscreen GmbH
Postfach 100 864
07708 Jena
Germany
Please enclose:
- the completed request form
To print this document you will need Acrobat Reader (Version 4.0 and up). - For patients within the German public health insurance system we need the “Überweisungs- Abrechnungsschein für Laboratoriumsuntersuchungen (Nr. 10)"
Please do not forget to print the name and telephone number of the doctor treating the patient, for the purposes of our reply.
The specimen needs to be sent in a padded envelope without being cooled and it needs to arrive at the laboratory within 24 hours after blood has been taken. Within Germany, we guarantee a reply within 5 working days after arrival of the parcel at Oncoscreen.
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Scientific Background
Polycythemia vera (PV) is a chronic myeloproliferative disorder and occurs at an incidence of 30 per 1 million people - about twice as frequently as the chronic myeloid leukemia (CML).
Before the availability of the prv-1 test, PV was to be diagnosed exclusively on the basis of clinical criteria but this has several problems. First, there is dissent among experts concerning the criteria. Second, the symptoms are not always clearly developed, especially not in patients at early stages of the disease. Therefore in particular the differential diagnosis is between PV and secondary erythrocytosis sometimes is not possible and the risk of a false diagnosis and subsequently of a wrong treatment for the PV patients is high.
Patients with an untreated PV can die within 18 months but patients who are appropriately treated have a median survivalof 15 more years. Hence, an accurate, reliable, and prompt diagnosis is very crucial for these patients. Furthermore, because chemotherapy in use (Hydroxyurea, Anagrelide or Interferon, respectively) can cause adverse side effects, any chemotherapy based on wrong diagnosis must be avoided.
Most recent scientific results show that the prv-1 gene expression in granulocytes of PV patients is dramatically elevated. The prv-1 test is based on this finding and utilizes the technology of quantitative real time RT-PCR. With this test Polycythemia vera now can be diagnosed with a specificity of 95 % and a sensitivity of 95 %. The prv-1 test, especially, enables allows a reliable differential diagnosis to be made between PV and the secondary erythrocytosis.
Additionally, the PV-1 test can be used to diagnose the essential thrombocythemia (ET). About 50 % of all patients with the clinical symptoms of ET show an elevated prv-1 gene expression. This subgroup has a drastically heightened risk of thromboembolic complications and a high probability of transformation of ET into PV. Hence, it is very important to determine the prv-1 gene expression of the ET patients to design an optimal therapy management.
This test has been offered as a routine diagnostic test since June 2003. About 500 patients have been tested so far. This demonstrates very strongly the clinical need of such a differential diagnostic tool.
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How is the diagnosis performed?
The granulocytes are isolated from the EDTA blood sample using a Ficoll gradient centrifugation step. The RNA of the granulocytes is transcribed into so-called cDNA, which is used in a quantitative RT-PCR to determine the prv-1 gene expression. If the prv-1 expression is higher than in the normal population, the patient has developed the Polycythemia vera. The threshold values for determining the results have been validated statistically. In about 5 % of the cases, the answer is not unequivocal. In these cases we recommend another analysis within the next three months
Literatur
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Oncoscreen®
Loebstedter Str. 93
07749 Jena
Germany
Phone: +49 (0) 3641 / 5074-0