Prisons (Drugs) (Hansard, 10 December 1996)

§ Miss Widdecombe

Responsibility for this matter has been delegated to the Director General of the Prison Service, who has been asked to arrange for a reply to be given.

Letter from Richard Tilt to Mr. George Howarth, dated 10 December 1996: The Home Secretary has asked me to reply to your recent Question about representations received concerning the accuracy of drug tests carried out by the Prison Service. Mandatory drug testing is a new procedure, and as such has been subject to several representations, including some about the accuracy of the drug tests carried out. Individual prisoners may also have raised concerns through the requests/complaints procedure, but these are not recorded centrally. Prisoners have a right to challenge the results of a test specifically by requesting an independent analysis of a portion of the sample they provided which is retained for this purpose. Release of this sample is authorised at Prison Service Headquarters. To date 15 requests have been received from solicitors acting on behalf of prisoners in challenging the result of a particular test. These requests include supply of the sample itself, for the purposes of independent analysis, or for the documentation which supports the initial test result. In addition, on 7 May the Head of Healthcare at HMP Wealstun noted that there were conflicting results on the same inmate on occasions when he had done a voluntary drug test, analysed at Harrogate District Hospital within a day or so of the Mandatory Drug Test. He was asked to furnish the data which led to his concerns so that investigation could take place and remedial action taken as necessary. These details have not been furnished and so the specific cases have not been followed up. There always will be differences in the results of tests used by medical officers for therapeutic purposes and those produced through the Mandatory Drug Testing programme since the purposes are different. The latter operates to agreed threshold levels, and prisoners are only found to have tested positive once this threshold is exceeded. This is to ensure that when a charge is laid on the basis of a positive confirmation test result it is beyond reasonable doubt that the prisoner took the drug in question. Some changes have been made to the method of testing for opiates since July which now ensure that opiate use is more likely to be picked up from a Mandatory Drug Test. On 15 July the Chairman of the Board of Visitors at Downview prison raised concerns about three prisoners who had screened positive for opiates and three who had screened positive for benzodiazepines in early June. All had been found negative through confirmation testing. The opiate results were attributed to the absence of an hydrolysis process from confirmation testing, which resulted in a number of samples that correctly screened positive for opiates confirmation testing negative. Hydrolysis was introduced on 2 July. In two of the cases involving benzodiazepines, the prisoners had been prescribed a combination of medications which cross-reacted with the reagent used in the screening test. Confirmation testing uses a different technology which avoids such cross-reactions. In the third case it is thought that the sample may have been positive for an uncommon type of benzodiazepine which is not recognised in confirmation testing. The Prison Service, in conjunction with the Laboratory of the Government Chemist, is considering ways of extending the range of drugs detected by confirmation testing. 147W On 5 August the Kent Area Manager raised concerns about six samples from Blantyre House prison which had screened positive for cannabis, but were all found to be negative on confirmation. It was discovered that for a period of 1½ hours on 5 July the screen testing machine had been mis-calibrated, producing 84 false positive results, all prisons affected were notified. The Laboratory of the Government Chemist has since introduced more rigorous quality control procedures, ensuring that results do not leave the laboratory until all checks have been made.