Issue 18 // July 2015

Transcription

1 Issue 18 // July 2015 Coeliac screening: changes to current protocol Dr Miriam Hurst Pge 2 Throat Swabs in the Auckland community setting Dr Arlo Upton Pge 4 Non venepuncture specimen collection update Pge 5 Scabies examination Janet Wilson Pge 2 Repeat test requests: process changes Pge 4 Continuing education for general practitioners Pge 6 Fungal collections for microscopy and culture Janet Wilson Pge 3 Accurate documentation - pregnancy status Pge 5 Semen Collection and specimen labelling policy Pge 6 It is hard to believe that we are half way through This year I have been working on several projects in microbiology and the wider laboratory. You will be aware that we have made some changes to how we manage repeat test request forms to ensure that they are reviewed, as is clinically appropriate, in a timely fashion. We have also clarified what specimens are appropriate to be obtained from the patient at our collection rooms and what should be collected by medical or nursing staff in primary care. Perhaps most contentiously I believe that nasopharyngeal swabs should not be collected by phlebotomists at community collection centres; for both scope of practise and public health reasons. You can find further information about this in our Lab Update (1/7/15). While I appreciate that some of our referrers will consider these changes a reduction in service they are largely consistent with other community laboratories around New Zealand and have been made following consultation with clinical appropriateness taking priority over logistical considerations. We are pleased to announce that we are introducing a new faecal occult blood (FOB) testing method at Labtests. The new method is more specific and doesn t require dietary changes pre-testing, and is the same method currently in use by the Waitemata pilot programme. FOB testing is another controversial area of the laboratory. FOB testing at Labtests is restricted to patients aged 50 years or < 1 year, and where other faecal pathogens have NOT been concurrently requested. This policy has been discussed extensively with the three Auckland DHB gastroenterology department heads. They re-iterate that symptomatic patients should be referred and that FOB testing does not have a role in the diagnostic work up of iron deficiency anaemia. Patients with a family history of colorectal cancer should also be referred without FOB testing. Another exciting change in the microbiology laboratory is the introduction of a molecular test for Salmonella species, Shigella species, Campylobacter species, and vero-toxin producing E. coli. Culture continues to be performed on specimens positive for pathogenic DNA, and for Yersinia species (routinely). The molecular test also detects Giardia lamblia and Cryptospordium parvum. We are closely monitoring the performance of the test with Auckland Regional Public Health. At this time referrers won t notice much difference except that negative results are available a day earlier. Please remember to send in ONLY ONE FAECES SPECIMEN. We still see patients in whom three samples are requested; this is almost always unnecessary, unpleasant for the patient, and expensive. Dr Arlo Upton Medical Director Labtests arlo.upton@labtests.co.nz June sees the end of our financial year and board approval of next year s budget. I am pleased to report that several of my projects have been approved including the opening of a new and additional collection centre in Takanini. We chose Takanini as it is located between two of our busiest Counties centres; Manurewa and Papakura, where the pressure of increasing population is putting unacceptable strain on the existing staff and facilities, not to mention patient waiting times. The new collection centre will be located in a new building where there is already a busy medical centre, pharmacy, and soon to be opened radiology centre. There will be ample parking in the vicinity as well as good disabled parking and access. We will widely publicise the opening of the Takanini centre when the fit out is complete. A refurbishment of our Mercy hospital collection centre has recently been completed, much to the delight of the staff and patients. The budget also has provision for the new occult blood testing and the molecular test for faecal parasites mentioned above by Dr Upton. By ensuring there is only appropriate testing we can better direct limited resources to employing better technology for a better outcome. As Labtests has been operating for six years we have commenced a complete refresh of The Scope, Issue 18, July our main biochemistry platforms, this will see eleven new replacement analysers installed between now and the end of September. In addition we have replaced the coagulation analysers with state of the art units. This is an investment of over $2 million and will put us in a good position to meet future demand and ensure continuous service. Over the last three years Labtests has supported the Auckland Rescue Helicopter. This year I doubled our usual donation to $10,000 as we acknowledge that huge contribution this voluntary organisation makes to the healthcare of our community. Mike Norriss General Manager, Labtests Mike.norriss@labtests.co.nz

2 Coeliac screening: changes to current protocol Background Coeliac disease is an autoimmune disorder in which the body reacts adversely to gluten. The gold standard for diagnosis is a small bowel biopsy showing the characteristic villous atrophy; however, as this is an invasive procedure, the vast majority of patients will first have screening blood tests done. These look for the autoantibodies that are associated with coeliac disease. Both biopsy and coeliac screening tests need to be done in patients who are currently eating gluten (2-4 slices of wheat-based bread or equivalent per day). Patients with positive antibody tests should be considered for endoscopy and biopsy. If antibody tests are negative but the patient has a strong personal and/or family history endoscopy may also be appropriate. Genetic testing for the HLA DQ2/DQ8 genes associated with coeliac disease is not dependent on diet and may be useful when the diagnosis is less clear. However, it is mainly useful in excluding the diagnosis if the gene test is negative, as not all people with the gene will have the disease. Labtests Each month Labtests performs coeliac screening tests, of which 2-3% are positive. Currently we perform IgA tissue transglutaminase (ttg) antibodies, total IgA, and IgG deamidated gliadin peptide (dgp) antibodies in all patients. If IgA ttg is positive we perform endomysial antibody testing (EMA). Because the ttg antibody is an IgA antibody, we need to perform the total IgA as If this is low IgA ttg antibody may also be low/negative. This is especially important as low IgA is associated with an increased risk of coeliac disease. IgG antibodies such as the IgG dgp antibody are not affected. Occasionally we find patients where IgG dgp antibody is positive but IgA is normal and IgA ttg is negative. Most authorities believe isolated IgG dgp positive results are only significant in patients with IgA deficiency. After consultation with hospital adult and paediatric specialists we are now moving to doing IgA ttg and total IgA in all patients, but only performing IgG dgp if the IgA is low. This is in keeping with international and local guidelines, including the new Starship screening guideline. All other testing remains the same. Anti-gliadin antibodies are no longer thought to be useful as part of standard screening. International research has suggested it may be possible to diagnosis coeliac disease in the paediatric population by antibodies alone. This approach is undergoing investigation in the Auckland region; currently. Biopsy should be considered for all patients. Please contact us if you have any questions about this change. Dr Miriam Hurst Immunopathologist // miriam.hurst@labtests.co.nz References: Coeliac NZ website: Husby S, Koletzko S, Korponay-Szabó IR et al. (2012). European Society for Pediatric Gastroenterology, Hepatology, and Nutrition guidelines for the diagnosis of coeliac disease. J Pediatr Gastroenterol Nutr; 54: Ludvigsson J, Bai J, Biagi F et al. (2014). Diagnosis and management of adult coeliac disease: guidelines from the British Society of Gastroenterology. Gut; 63: Scabies examination Examining patients for proof of scabies is a technically challenging process to perform and the diagnosis is usually made clinically. Please refer to this helpful bpac article: magazine/2009/february/docs/bpj19_scabies_pages_12-16.pdf Laboratory diagnosis is based on microscopic identification of the scabies mites (Sarcoptes scabiei), mite eggs, or the presence of mite faecal material. But a negative test does not rule out scabies. DermnetNZ says: Even experienced dermatologists only recover a mite or an egg in about 50% of cases of scabies. The mites are located under the surface of the skin; therefore scrapings must be made from the infected area (papule). See illustrations. Note scabies mite speck at end of track on right, characteristic of Sarcoptes scabiei To perform the test the following items are required: Gloves, Gown, Mineral Oil, Scalpel Blade, 2x Slides, Slide holder, Cellotape and a Pencil Method: Using a pencil clearly write the patient s full name and date of birth on the frosted end of the slide. Place 1-2 drops of mineral oil on a sterile scalpel blade. Allow some oil to flow onto the papule. Scrape vigorously six or seven times to remove top of papule. Transfer the oil and scraped material to a glass slide using the same scalpel blade. Then add 1 drop of mineral oil to the slide and stir the mixture. Place another glass slide over the slide and stick them together using sticky tape. Place this specimen slide in the slide holder and close it firmly. Place the labelled slide holder (containing specimen slides) into a biohazard bag and seal it securely. The Scope, Issue 18, July

3 Scabies Examination cont. Scabies mite under microscope Scabies scybala (mite faeces) Prepared by: Janet Wilson HOD Microbiology Labtests Tracking and blisters Note black scabies mite speck on right of track Fungal Collections for Microscopy and Culture GENERAL INSTRUCTIONS SKIN SCRAPINGS Fungal microscopy and culture is used in the investigation of suspected yeast, tinea/ringworm (dermatophyte infections). Before performing a skin scrape it is important to check with the patient whether the affected area has been treated with any antifungal/antibiotic ointment or cream. If the patient has applied an antifungal/antibiotic ointment or cream to the site to be tested within the past 24 hours, the scraping cannot be done at that time. Remove the cream with an alcohol swab and request the patient to come back after a minimum of 24 hours. NAIL CLIPPINGS Cleanse first with 70% alcohol to reduce bacteria and saprophytic fungi. Wait until alcohol dries. Note: Do not use alcohol wipes on open lesions. 1. Wear gloves 2. Collect the specimen Cleanse skin lesions first with 70% alcohol to reduce bacteria and saprophytic fungi. Note: Do not use alcohol wipes on open lesions. If lesions are open then use a cleansing wipe which is alcohol free. Wait until cleansing solution dries. With reasonably vigorous action, obtain scrapings using a sterile scalpel blade from the whole of the infected area, but particularly the peripheral raised reddened area typical of fungal infections. Note: It is important to scrape this area as it is where the active infection is. As much material as possible should be obtained from the skin surface so that there is ample for both culture and microscopic examination. Blisters, especially from the sole, should have the roof removed. Place in a separate petri dish and label appropriately (this specimen has a high yield for dermatophytes) Place the specimen and the scalpel blade (if used) into a petri dish Collect as much sample as possible preferably obtaining nail as near as practicable to the active edge of the infection (just prior to infected nail). Note: It is important to collect as much material as possible from under the infected nail. Multiple sites require their own specimen, e.g. arm, leg or foot, use a separate petri dish and scalpel blade for each site. Please ensure each site is recorded on the petri dish Label the petri dish with collection site, patient details (full name, DOB) HAIR ANALYSIS Select hairs which are broken off and appear diseased, and pluck them with forceps. Hair samples should have skin scales collected and preferably 3-4 hair roots/follicle should be plucked (or scraped out if shaven face). If diseased hair stubs are not apparent, scrape the edges of a scalp lesion with a sterile scalpel blade. The Scope, Issue 18, July

4 Throat swabs in the Auckland community setting who should have them? Sore throats are complicated as they can be due to either viral or bacterial infection and it can be difficult to differentiate between the two on clinical grounds. Where the patient has other signs of an upper respiratory tract infection such as runny nose, cough, hoarse voice, or diarrhoea a viral infection is more likely. Aetiology of pharyngitis Viral infections 25 50% Group A streptococcus (children) 15 30% Group A streptococcus (adults) 10 15% Other bacteria < 5% Colonisation and infection with group A streptococcus (GAS) GAS commonly colonises the nasopharynx as well as skin, and so the isolation of GAS from a throat swab does not necessarily mean that it is causing the sore throat. The patient may have a viral pharyngitis with GAS colonisation. Unfortunately we cannot differentiate between colonisation and infection with any certainty. BUT if all patients with GAS isolated from throat swab are treated with antibiotics, some patients are receiving antibiotics unnecessarily. Antibiotics are not risk-free. Complications include gastrointestinal upset, rash and other allergy, and the development of antibiotic resistant bacteria. GAS pharyngitis is almost always a self-limiting infection; the main reason to treat it in our community is for the prevention in acute rheumatic fever (ARF). Therefore we recommend collecting a bacterial throat swab in the following patients: Maori and Pacific people aged 3 35 years People living in crowded circumstances aged 3 35 years Other people presenting with fever >38 C, tonsillitis, and adenopathy Swabbing of asymptomatic household members in families NOT at risk of ARF should be done only after consultation with microbiology, infectious diseases, or public health. Test of cure: Routine follow up (test of cure) throat swabbing is not recommended (unless related to ARF case). Who needs antibiotic treatment? Among patients at low risk for ARF only those who present unwell require treatment. Studies indicate that antibiotics reduce the duration of symptoms by (only) 16 hours. Antibiotics do reduce the incidence of suppurative complications but the number needed to treat is high. Patients at risk of ARF require antibiotic treatment for GAS pharyngitis. However, repeated GAS isolation may represent colonisation and this should be considered in a patient who has received several courses of antibiotics and in whom GAS continues to be isolated. Dr Arlo Upton Clinical Microbiologist arlo.upton@labtests.co.nz // IMPORTANT: Repeat test requests process changes for Labtests collection centre patients As notified in our laboratory update the following action has now been implemented for repeat test requests. 1. Forms older than one year are being removed from circulation Exclusions will be forms requesting INR and HbA1c these will be life-long provided there are no other tests requested on the same form. 2. When patients present with forms that are older than one year the patient will be bled and the form will be stamped expired. The following comment will go out with the laboratory results. Tests were requested on a repeat request form that is older than one year. If patient requires further regular testing, please issue another request form. If a patient presents with a form stamped expired the blood collection will not proceed. The Scope, Issue 18, July

5 Accurate documentation of pregnancy status is important Documenting pregnancy status is important for the lab to know so that appropriate reference intervals and interpretive comments can be provided with the result. Many normal results, and some critical calling thresholds, are different during pregnancy. The likely differential diagnosis of some abnormalities also differs. Labtests has noticed a trend for antenatal tests to be ordered pre-pregnancy. When you are ordering antenatal tests on a patient wishing to become pregnant it is important to document on the request form that she is not yet pregnant. Pregnancy is a time of significant physiological changes. These changes include increased plasma volume leading to haemodilution, increased egfr, modified glucose metabolism, and production and release of placental hormones. The table below summarises changes in laboratory findings during pregnancy and with the progression of pregnancy where relevant. Change in Reference range Change in critical calling limit Should not be tested in pregnancy Haemoglobin Oral glucose tolerance test (ogtt) MSU culture results are reported differently depending on pregnancy status ALT Uric acid Proteinuria # Anti-platelet antibody Alpha fetoprotein is naturally elevated during pregnancy Von Willebrand disease cannot be diagnosed with certainty because Von Willebrand factor and factor VIII increase even in the presence of Von Willebrand disease Other Slight increase in MCV during the second trimester Mild thromobocytopenia is expected towards the third trimester; levels as low as 80x10 9 may be considered normal Iron requirements increase so ferritin may decrease even when supplementary iron is given Fibrinogen, factor VIII and IX are increased in pregnancy egfr calculation is not validated for pregnancy therefore would not be provided There is an expected rise in ALP sourced from the placenta Gonadotrophins are naturally low or suppressed Prolactin is naturally high TSH is low or suppressed physiologically in healthy pregnancy Creatinine and urea drop due to haemodilution # proteinuria in early pregnancy (before 24 weeks of gestation) would not be caused by pre-eclampsia so would not need to be called as a critical result. Dr Samarina Musaad samarina.musaad@labtests.co.nz Phone: (09) Labtests non-venepuncture service: post-consultation update We have recently released a Laboratory Update outlining the changes in relation to the collection of swabs. The release is on our website These changes have been formulated after consultation and from the 13th July the following will apply: Wound, eye, ear, and throat swabs will no longer be collected at Labtests collection rooms Patients may present for self-collect vaginal swabs; however, these will not be collected by Labtests staff Genital swabs from symptomatic patients will not be collected at Labtests collection rooms Patients may present for self-collect MRSA swabs; however, these will not be collected by Labtests staff The collection of nasopharyngeal swabs will no longer be collected by Labtests staff at Labtests collection rooms. The following is a link to a Youtube video of collection of nasopharyngeal swabs: The Scope, Issue 18, July

6 LABTESTS CONTINUING EDUCATION FOR GENERAL PRACTITIONERS Labests is committed to providing support to practitioners and our pathologists are always happy to take calls regarding specific laboratory results. Another very effective way to help practitioners keep up to date with changing trends in laboratory testing and treatment is to invite one of our pathologists to attend your cell group meetings to speak on specific topics. To organise a pathologist for your cell group, contact Dr Arlo Upton: or arlo.upton@labtests.co.nz SEMEN TESTING SEMEN SAMPLES WILL NOT BE ACCEPTED FOR TESTING ON SUNDAY OR ANY PUBLIC HOLIDAY Semen for fertility assessment must be delivered to Labtests Carbine Road collection centre preferably within one hour, but not longer than one and a half hours after collection. (Note: not Sunday or public holidays). The specimen must be kept at body temperature. Post vasectomy semen samples can be delivered to any Labtests collection centre on the same day as collection. (Note: not Sunday or public holidays). Recollection of post vasectomy semen samples because further testing is required MUST BE TREATED AS SEMEN FOR FERTILITY, i.e. kept at body temperature and delivered to Carbine Road Laboratory within 1 hour. (Note: not Sunday or public holidays). Lab Tours for practice staff Labtests is operating regular tours of our laboratory for interested practice staff. Our tours have been a great success with visitors describing the experience as very helpful. This is your opportunity to get the answers to all your questions and to understand the processes involved in laboratory testing. The time spent counts towards your professional development portfolio. To book a place on one of our tours phone: Lorraine Elliot on // or her at lorraine.elliot@labtests.co.nz to register your place. SPECIMEN LABELLING POLICY In April of 2015, the Joint Advisory Group (JAG) endorsed the aligning of policies for specimen labelling across Auckland and the Northern region of the North Island. All Laboratories in the region are now expected to adhere to the labelling policy whereby two forms of the patient ID is a minimum requirement (e.g. two of the following three identifiers: the patient s full first and last names, date of birth, and NHI) and the identifiers on both the request form and the specimen must match. Labtests is committed to ensuring that issuing of results is both timely and accurate. We are required to comply with best practices, international, corporate, and regional standards. Labtests has always advised clinicians when an incorrectly labelled / unlabelled specimen has been identified and this practice will continue. In the first instance we strongly recommended a specimen recollect; however, we have also accepted written / verbal confirmations in some instances. Other Laboratories in the region have had slightly different process in dealing with these samples. There are the occasional instances where a recollect is not possible (see table below for detail). Therefore we kindly request a written confirmation to be received into the laboratory in a timely manner. This will ensure that the release of the result is not significantly delayed. Type of specimens that may be difficult to recollect Anatomical Pathology Requests Cytopathology Requests Requests for Children under the age of 5 Aspirate requests IUCD/IUD Renal Stones Cerebrospinal Fluid Urgent requests Urogenital Swabs 24hr urine requests How does this affect you? Labtests will no longer accept verbal confirmation on mislabelled or unlabelled specimens. Confirmation of the identity of specimen will only be asked for if the specimen is classified as a difficult collect; otherwise we will advise you that specimen requires recollection. If you would like any further details please do not hesitate to contact Saad Mansour Quality Manager, Labtests saad.mansour@labtests.co.nz The Scope, Issue 18, July