M. leprae. This disease is prevalent in areas of stagnant or slow flowing water. Infections with other atypical mycobacteria can involve the skin as well as other organs such as lymph nodes, lungs and meninges. The case presented is a 51-year-old farmer, resident in rural NSW, with a non-healing, rapidly growing ulcer on his left forearm of 2 months duration referred by his general practitioner to a surgeon. The typical histopathology and pathogenesis will be discussed. This case illustrates the importance of awareness of this skin infection, especially in extensive, non-healing, non-tumoural skin lesions. Obtaining a complete clinical history including the patient’s lifestyle, travel to endemic areas, and performing acid fast stains in any suspicious case with or without granulomatous inflammation, are measures that may assist in preventing delay in diagnosis and treatment of this disease. NOT EVEN A LITTLE BIT PREGNANT  CA COLON AS CAUSE OF FALSE POSITIVE PREGNANCY TEST B Dayanath 1 , I Simpson 1 , Z X Lu 1,2 , J C G Doery 1,3 1 Department of Pathology, Monash Medical Centre, Clayton; 2 Department of Clinical Nutrition, Monash Medical Centre, Clayton; 3 Department of Medicine, Monash University, Clayton, Victoria, Australia Introduction: Pregnancy testing is usually performed in women of reproductive age prior to any procedure which could potentially harm a developing embryo. Occasionally, false positive pregnancy tests may occur and have the potential to cause not only delay in treatment but also great consternation for the patient concerned. Patient: A 38-year-old female with advanced colorectal carcinoma (Duke’s stage 4) had serum beta human chorionic gonadotropin (hCG) tested prior to receiving chemotherapy. hCG was 74 IU/L which was interpreted as unambiguously positive. Chemotherapy was therefore delayed in spite of the patient believing she could not be pregnant. Investigations: The luteinising hormone (LH) and follicle stimulat- ing hormone (FSH) were normal for a woman of reproductive age. The initial result was confirmed on two alternate analysers and repeated 1 week later when it had risen to 84. Elimination of heterophile antibodies by use of Scantibodies and urine hCG confirmed the presence of free hCG. Performance of immunohis- tochemical staining of the original tumour collected 31 months earlier for hCG revealed patchy production of hCG in about 5% of the tumour population. This was seen predominantly at the advancing margin of the tumour. Discussion: An hCG of 74 IU/L is normally considered unambigu- ously positive and the absence of heterophile antibodies or peri/ post-menopausal source of pituitary hCG appeared to further increase the possibility of a normal or ectopic pregnancy. However the failure of the hCG to rise rapidly, a normal abdominal ultrasound and the protestations of the patient made further investigation necessary. The demonstration of hCG producing tumour tissue confirmed the likely origin of the circulating hCG. Conclusion: Laboratories must be constantly aware of the common sources of false positive pregnancy tests including heterophile antibodies, ‘macro’ hCG, pituitary hCG in peri/post menopausal women and tumour tissue itself. The production of hCG by germ cell tumours and teratomas is well recognised but the production by gastrointestinal cancers is much less well recognised. Recent reports suggest that non-trophoblastic tumours producing hCG are associated with a poor prognosis but a technique to stimulate anti-hCG antibodies may provide therapeutic promise. COMPARING MEASURED TCO 2 AND CALCULATED HCO 3 N Mohd Nasir, P Sthaneshwar, M Y Putri Junaidah, S F Yap Department of Pathology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia Aim: The objective of our study was to compare the measured total carbon dioxide (TCO 2 ) and calculated bicarbonate (HCO 3 ), and to determine the agreement between these two values. Methods: TCO 2 and HCO 3 values of 1820 samples drawn at the same time from the patient were compared. TCO 2 was measured from venous samples analysed on Dimension RxL while HCO 3 was obtained from arterial blood gas samples analysed on Radiometer ABL 700. Results: The TCO 2 and HCO 3 values correlated well (r 0.977, p B 0.001), with the correlation given by the equation, y 0.986  0.5335. Using Bland-Altman analysis, the bias was 0.87 mmol/ L (SD 1.42 mmol/L), and the 95% limits of agreement (LOA) were 1.92 to 3.67 mmol/L. Story and Poustie criteria were used to study the agreement between these two methods. Based on the first criterion, the bias was less than 91 mmol/L. As per the second criterion, the LOA between both methods should range between bias 92 mmol/L or a total span of 4 mmol/L, but the LOA was more in our study. Conclusion: TCO 2 did not show good agreement with HCO 3 . Clinicians should be aware of this discrepancy and hence should be cautious when using HCO 3 for management of acid-base disorders. COMPLETING THE AUDIT CYCLE: A STUDY ON THE IMPACT OF CHANGES TO A CORE LABORATORY’S RECEPTION ON TURNAROUND TIME OF ROUTINE SAMPLES Johan van Wyk, Louise Nutt, Annalise E Zemlin, Rajiv T Erasmus Division of Chemical Pathology, National Health Laboratory Service (NHLS), Tygerberg Hospital, Stellenbosch University, Parow, South Africa Aims: This study investigated the role of a core laboratory’s reception area on turnaround time (TAT), assessed the impact of change and highlighted those areas where most delays were incurred. Methods: The time-intervals of randomly selected specimens were documented throughout the test-cycle, before and after changes to a core laboratory’s reception area. Data were analysed using non- parametric methods. Results: Significant improvement was noted (p B0.0001) to TAT in the reception area, the pre-analytical phase (p 0.0035) and total TAT (p 0.0442). The pre-analytical phase comprised the largest component for TAT in 2007 and 2008 (69.9% and 64.0%, respectively.) The data showed marked delays in the pre-analytical phase, with sample collection and transport constituting 25% of the total TAT. Discussion: TAT is an important component in the evaluation of laboratory quality assurance. Laboratories have limited control 82 PATHOLOGY UPDATE 2009 ABSTRACT PUBLICATION