What does not work !
Standard aggregation studies (particularly those using a PFA100) are NOT a reliable and sensitive method to test for Hermansky-
Clear guidance has been issued in the UK regarding the use of standard aggregometry (in particular, the PFA100) to test for mild platelet bleeding disorders including HPS (Click here). A number of reviews and research studies have also been published. Results from this method often do not show the platelet defect of of HPS. Such ‘false negative’ results may lead a doctor to exclude a diagnosis of HPS prematurely. Other tests carried out using the same blood may confirm a diagnosis of HPS.
If standard aggregometry is carried out (including with the PFA100) then it should be backed up by either a nucleotide assay or electron microscopy.
Ask your haemotologist what approach they are going to use and ask them to use a combination of Methods.
Standard laboratory tests for blood clotting (coagulation times) DO NOT identify the platelet defect of HPS. These include:
Coagulation times vary greatly from within normal range to outside normal range for those with HPS and so are not a reliable indicator for the platelet bleeding disorder of HPS. More importantly the platelet defect of HPS is simply not measured by any of the above coagulation tests
However, the above tests of coagulation are carried out routinely within the UK National Health System (NHS) when a bleeding disorder is suspected. This is an important safeguard because unrelated conditions can result in a pattern of bleeding symptoms similar to HPS.
This is also regarded as an unreliable indicator of for ‘mild’ bleeding disorders. This test involves making a small incision on the skin of the forearm and timing how long it takes for the blood to stop flowing from the cut. The cut is typically made using a small spring loaded ‘punch that makes a incision of a specific length and depth.
Due to the wide variation in the bleeding tendency it is not sufficient to exclude a diagnosis of HPS due to an apparent lack of a clear history of bleeding -
The hair bulb test
It is possible for a person with albinism to have a bleeding disorder caused by a separate medical condition that is unrelated to either albinism or HPS.
It is also possible for someone with HPS to have a coagulation disorder in addition to that caused by HPS.