Dear Colleague,

 

I have had the following request from Jon Copsey at Sherwood Scientific Ltd. With regard to their 926S chloride meter which is widely used for measuring sweat chloride.

 

We have, up to now, been supplying the M926S worldwide via our distributor network.  However, recently we have been advised we have to stop selling the device for the purpose of cystic fibrosis determination, firstly by the FDA in the USA and then by Health Canada because the device is not registered with those two organisations for that purpose.

 

In our discussions with the FDA it is clear we have to present evidence the device is fit for purpose; somewhat ironic given it has been used for that purpose without complaint (the opposite in fact) for more than 30 years (the current 926s is in essence the Corning 925 which was in existence in the early 80’s).  However, we have no choice but to observe their direction and register the product with them for that purpose if we wish to continue to sell.

 

Presentation of data to confirm precision, linearity etc. obtained by analysis of calibrators and controls over the range relevant to the sweat chloride test is not an issue for us. 

 

However the FDA’s requirement we provide data to indicate the instrument is capable of identifying non-elevated, intermediate and elevated chloride levels in real sweat samples from pools of individuals by comparison of results for the groups from our instrument with results from a predicate device is something I believe we have no possibility to achieve on our own.

 

And so my question is; do you know of any group or individual who might have conducted such a trial with one of our instruments and whom we could approach to discuss the possibility to share their results/data.  Alternatively could you recommend an individual or group with whom we could discuss the possibility to conduct such a trial(s)?

 

We seek sweat chloride data generated using a Sherwood 926S for real patient sweat samples.  Data should be for duplicate results and patient numbers would preferably be in excess of 40.  Where possible the sweat chloride results obtained would have also been confirmed by an alternative (specified) method.  In addition it would be useful if the data set spanned the measurement range for chloride of 10mmol/l up to greater than 100mmmol/l and that those samples with sweat chloride results >60mmol/l could also be confirmed to have come from  patients who had indeed been confirmed to have Cystic Fibrosis.  No patient identification data is required but the age range of the patient group is required and the age of patients whose sweat chloride results sit close to the 30 and 60 mmol/l decision points may be required.  The data must be freely available to share with third parties.

 

In addition if any lab is using or is in possession of an old Buchler-Cotlove Chloridometer (last manufactured/owned by Labconco) we would be grateful if they could make contact.

 

 

If anybody is able to assist Jon, please direct your responses to him directly.

 

Many thanks

 

Paul

 

Paul Griffiths

Consultant Biochemist

Head of Department & Director of Newborn Screening

Newborn Screening and Biochemical Genetics Dept.

Paediatric Laboratory Medicine

Birmingham Children's Hospital

Tel +44 (0)121 333 9923

 

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