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NWL Awarded UKAS Accreditation to ISO 17025 for Clinical Pathology
Currently there is no statutory requirement for veterinary laboratories or medical laboratories for that matter, to demonstrate their competence or the validity of their results. Some laboratories have subscribed to the ISO 9001or 9002 quality standard but this can only be applied to administrative and management procedures, these standards specifically do not demonstrate the competence of the laboratory to produce technically valid data and results. However there is an international standard for testing laboratories, ISO 17025. This ISO standard contains all of the requirements that testing laboratories have to meet if they wish to demonstrate that they operate a quality system, are technically competent and able to generate technically valid results. In the UK accreditation to this standard is administered by UKAS, the United Kingdom Accreditation Service, an organisation under the control of the department of Trade and Industry. The standard is applicable to all types of laboratories. Until recently the only laboratories with UKAS accreditation serving the veterinary profession were in the public sector eg. VLA, PHLS, SAC. We are delighted to be the first private commercial veterinary laboratory in the clinical pathology sector to be granted UKAS accreditation to ISO 17025 for clinical pathology services in haematology, biochemistry, microbiology and parasitology. We believe that it is no longer sufficient for veterinary surgeons to assume that a laboratory is technically competent and that the results they produce are valid. Professional reputations and livelihoods are increasingly dependant upon such results. Accreditation is the way forward and NWL are pleased to be leading the way. Top
Once a sample has been collected it should be protected from heat and light whilst stored, or during transport to the laboratory. Blood sampling needs to be planned to minimise delays in transit – blood taken on a Friday evening before a Bank Holiday weekend is unlikely to make a useful contribution to any diagnostic work-up! The affect of haemolysis on red cell indices acts to reduce red cell numbers and haematocrit, due to loss of intact cells, whilst the MCHC appears increased as the total haemoglobin content remains unchanged. Substances present in high concentration within red cells, for example certain enzymes and electrolytes will, during the process of haemolysis, leak out into the sample and lead to spurious results following analysis. This applies to AST, LDH, and phosphorus and to a lesser extent potassium. Particularly high levels of potassium are, however, contained in red cells of some Japanese Akita’s and English Springier Spaniels, haemolysed samples from these breeds can produce some alarming (even heart stopping!) hyperkalaemias. As previously mentioned, haemolysis imparts a red colour to serum/plasma, the intensity of which is proportional to the degree of haemoglobin released, and this will interfere with photometric methods of biochemical analysis. This situation affects plasma proteins, and cholesterol, all of which tend to be increased, whereas calcium, AP and bilirubin may be decreased. Lipase and glucose may be increased or decreased, so take your pick! It is worth pointing out that UV light (sunlight) dramatically reduces bilirubin levels by (approximately 50%/hour. See Table 1. In a recent “in-house” study of the effects of sample ageing and haemolysis significant deviations from day 1 “normal” results were observed with several analytes. In addition to the predicted trends, bile acids were significantly affected by even mild haemolysis and creatinine values fell outside the normal range with mild to moderate haemolysis. Approximately 10-15% of the samples received by the laboratory are affected by mild haemolysis, therefore a degree of caution must be employed when evaluating abnormal results. Extensively haemolysed sample results are fortunately quite rare, but results are likely to be distorted and cannot be considered representative or interpreted reliably. The problem of haemolysis can be minimised or avoided by following a few simple guide lines: 1. Take blood from fasted patients as lipaemia increases red cell fragility.Finally, and in a slightly different vein (!), samples for haematology may be unavoidably traumatised in transit, especially during hot weather, petrol shortages and postal strikes! Please remember to submit several air dried fresh smears, since this enables a much more accurate assessment of cell morphology and can only enhance the diagnostic value of your haemogram. Table 1
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The Relaxin test is used as a marker for canine pregnancy. The test is claimed to be sensitive from 21 days post fertilisation. However the test has been troubled by false negatives. This was thought to be related to confusion over the date of fertilisation. Because of delay in sperm transport and actual implantation, the date of fertilisation can be as much as 5 days later than the date of insemination. Handleman et al in an evaluation of 40 bitches observed that the test was sensitive to litter size and noted that small litter sizes (1 - 4) may predispose to false negative results when tested at 25 days. The sensitivity of the test for pregnancy at 25 days was estimated to be 70%. They advised that testing should be delayed to 30 days which increased the sensitivity to 75%. They advise that animals should be tested at 30 days. In a recent case a bitch with a litter of 3 pups had a negative Relaxin result at 30 days. It may be advisable to retest negative bitches again at 35 days. It should also be noted that the test may also give rise to false positive results due to resorption or abortion of the litter. It is important when submitting to give an accurate mating date as this can help with the interpretation of borderline results. Reference
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Venue: Myerscough College, Bowland Suite, Bilsborough, Lancashire Speaker: Geoff Skerritt BVSc Dip ECVN CBiol MIBiol FRCVS: “Scratching Cavaliers” and “Arnold-Chiari Syndrome” Case book studies: If you would like to present an interesting case please contact Jane Miller on 01253 899215 or mail at nwlabs@nwlabs.co.uk To book your place, request further information or a location map call Joanne Kenyon on 01253 899215 mail to nwlabs@nwlabs.co.uk Top
Thurs 10th January 2002IMPORTANT - The current speaker programme is proving very popular. Due to a restriction on the number of bodies we can accommodate please make sure you reserve your place early. If you have to cancel we would appreciate a call. Quote “An excellent way to
top up my CPD
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NEW
TEST
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Wounded cats - wild and domestic
cats - purr because it helps their bones and organs to heal and grow stronger,
say researchers who have analysed the purring of different feline species.
The scientists, from the Fauna Communications Research Institute in North
Carolina, found that between 27 and 44 hertz (a measure of the number of
cycles per second) was the dominant frequency for a house cat. This reinforces
studies confirming that exposure to frequencies of 20-50Hz strengthens
human bones and helps them to grow.
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