Elastinfibrer ger blodkärl och andra vävnader deras flexibilitet. Elastinfärgning är relevant när man misstänker melanom, temporalis artrit, venös invasion och efter blodkärlsoperationer. Syftet var att med hjälp av olika vävnadstyper optimera och implementera den automatiserad elastinfärgningen enligt Hart, för att ersätta den nuvarande manuella elastinfärgning enligt Verhoeff vid patologilaboratoriet på länssjukhuset Ryhov, Jönköping. Colon, njure, hud samt navelsträng färgades med den automatiska metoden enligt Hart för att hitta optimala inställningar. Vävnader från samma områden färgades med den manuella metoden enligt Verhoeff samt den automatiska metoden enligt Hart för att jämföra dem. Snitten bedömdes av en läkare så allt färgades som det skulle. Optimeringen av Harts metod resulterade i en inkubationstid på tolv minuter samt en optimal färgningsbehandling utan xylen. Resultaten av jämförelsen mellan den automatiska metoden enligt Hart och den manuella metoden enligt Verhoeff visar att den automatiska metoden enligt Hart ger bättre kontrast samt bakgrundsinfärgning. Slutsatsen blev att den automatiska metoden enligt Harts var bättre än den manuella metoden enligt Verhoeff, att i framtida studier studera möjligheten att byta ut läskningen mot till exempel ytterligare ett etanoldop samt att byta ut snitten av navelsträngen mot snitt av lever. / Elastic fibres ensure blood vessels and other tissues flexibility. Elastic staining of tissue is relevant when there is suspicion of melanoma, temporalis arteritis, venous invasion and after operations on blood vessels. The aim of the study was with the help of different tissue samples optimize and implement Hart´s elastic staining method as a substitute for Verhoeff’s at pathology lab at county hospital Ryhov, Jönköping. Colon, kidney, skin, and umbilical cord cross section got stained with Hart´s automated elastic staining method to evaluate the optimal staining procedure. Same region of the tissues was stained with Verhoeff´s manual elastic staining method and Hart´s method. All cross section were assessed and compared with the help of a pathologist doctor. Optimization of Hart´s method resulted in an incubation period of twelve minutes and optimal staining procedure without xylene. Result of comparison between Hart´s staining method and Verhoeff´s staining method showed that Hart´s staining method had a better contrast and background. Conclusions of the study was that Hart´s staining method was better than Verhoeff´s staining method, further studies could include research about a substitution of the blotting step with an extra ethanol bath as an example and liver tissue instead of the umbilical cord.

Urinblåsecancer är den sjunde vanligaste cancerformen i Sverige där blåssköljvätska utgör det huvudsakliga provmaterialet vid utredning. ThinPrep® är en vanligt förkommande metod som används inom vätskebaserad cytologi vid analys av blåssköljvätska. Fixering av provmaterialet kan försvåra diagnostiken på grund av förändrad morfologi samt artefakter.  Studiens syfte var att jämföra erhållet preparatinnehåll från blåssköljvätskor som fixerats med fixeringslösning innehållande ättiksyra med CytoLyt® solution. Studien ämnade även jämföra ThinPrep® filtren ”Non-GYN” och ”UroCyte”.  Studien inkluderade 90 patientprover av blåssköljvätska som fixerades med tillsats av ättiksyra samt CytoLyt®, varvid filtren ”Non-GYN” samt ”UroCyte” användes. Preparaten bedömdes av cytodiagnostiker samt cytopatolog utifrån kriterierna: bakgrundsmaterial, cellmängd samt färgbarhet. Resultatet visade att CytoLyt® i kombination med filtret ”Non-GYN” gav ett mer representativt preparat samt lämnade en god bakgrundsbild. Användandet av CytoLyt® resulterade i fler diagnostiska fördelar jämfört med fixering av ättiksyra, vilket även gynnar patienter. / Bladder cancer is the seventh most common form of cancer in Sweden where the main source of material for investigation are bladder washings. A common method within liquid-based cytology for analysis of bladder washings is ThinPrep®. Altered morphology as well as artifacts due to fixation can complicate funkar “the diagnostics of the sample. The aim of this study was to compare the slide content obtained from bladder washings fixed with fixative containing acetic acid with CytoLyt® solution. The study also intended to compare the ThinPrep® filters "Non-GYN" and "UroCyte". A total of 90 samples of bladder washings from patients where included. The samples where fixed with the addition of acetic acid and CytoLyt®, using the "Non-GYN" and "UroCyte" filters. A cytotechnologist and a cytopathologist assessed the preparations based on the criteria background material, cell quantity and the amount of colour change. The results showed that CytoLyt® in combination with the filter "Non-GYN" gave a more representative preparation and provided a good background image. The use of CytoLyt® resulted in more diagnostic benefits compared to fixation with acetic acid, which also benefits patients.

[pt] A participação de laboratórios clínicos em programas de ensaio de proficiência é uma importante ferramenta para gestão da qualidade. A maior parte das avaliações de desempenho de laboratórios clínicos por ensaio de proficiência se realiza com base no critério Z-Score, cujo valor designado é o consenso de resultados obtidos pelos participantes da rodada de proficiência, que é fortemente dependente da qualidade dos sistemas analíticos dos participantes. Utilizando uma base de dados fornecida por um provedor de ensaios de proficiência acreditado pelo INMETRO, este trabalho compara o desempenho de critérios para a avaliação da proficiência de laboratórios clínicos para medição de glicose. Consideraram-se não só critérios comumente utilizados, mas também novos critérios propostos que independem do consenso, baseados apenas em parâmetros associados ao valor designado pelo material de referência. As discrepâncias de classificação de desempenho dos laboratórios em função dos critérios de avaliação empregados indicaram inadequações da classificação baseada em critérios com parâmetros afetados pelo consenso entre participantes. O estudo também permitiu caracterizar o desempenho dos sistemas analíticos empregados pelos participantes, evidenciando-se uma discrepância significativa entre seus resultados. Os resultados do presente trabalho possibilitam analisar o impacto dos critérios utilizados no ensaio de proficiência para a adequada avaliação do desempenho dos laboratórios, contribuindo, assim, para a garantia da confiabilidade dos diagnósticos clínicos e condutas terapêuticas. / [en] The participation of clinical laboratories in proficiency testing programs is an important tool for quality management. Most evaluations of clinical laboratory performance by proficiency testing are carried out based on the Z-Score criterion; whose assigned value is the consensus of results obtained by the participants of the round, which is heavily dependent on the quality of analytical systems of participants. Using a database provided by a proficiency testing provider accredited by INMETRO, this paper compares the performance of criteria for the assessment of proficiency of clinical laboratories for measuring glucose. The analysis considered not only commonly used criteria, but also new proposed criteria that are independent of the consensus effect, based only on parameters associated with the assigned value defined by the reference material. The observed discrepancies in the performance rating of laboratories, according to the evaluation criteria employed, allowed the evidencing of inadequacies in the classifications based on criteria using parameters affected by the consensus among participants. The study also characterized the performance of analytical systems employed by the laboratories, evidencing a significant discrepancy between the results its. The present work allowed a better understanding of the impact of criteria applied in proficiency testing programs on the adequacy of evaluation of laboratories performance, thus contributing to ensuring the reliability of clinical diagnostics and therapeutical procedures.

Inom klinisk verksamhet är det av stor betydelse att känna till hållbarheten på olika analyter för att säkerställa att analysen inte genomförs på för gamla prover. Vid litteratursökning framgick att bland de publicerade studier som undersökt hållbarheten på blodprover har de flesta undersökt hållbarheten på venösa men inte kapillära blodprover. En vanligt förekommande analys med både venösa och kapillära prover är blodstatus, som inkluderar bland annat bestämning av hemoglobinkoncentrationen (Hb-), leukocyt- samt trombocytpartikelkoncentrationen (LPK och TPK). Analys av blodets celler kan ge allmän information om hälsotillståndet hos patienter och är därav viktiga och vanligt förekommande analyser. Syftet med examensarbetet var att undersöka hållbarheten för analyserna Hb, LPK och TPK på kapillära blodprover efter fyra och sex timmars förvaring i rumstemperatur. Provmaterialet utgjordes av 100 kapillära prover som analyserades på hematologiinstrumentet Sysmex XN-10. Analysmetoden för Hb var fotometri med natriumlaurylsulfat- (SLS-) metoden. LPK bestämdes med flödescytometri medan TPK bestämdes med impedansmetoden alternativt flödescytometri. Resultatet visade att det för Hb inte förekom någon signifikant statistisk skillnad mellan den initiala analysen och efter fyra respektive sex timmar. Analysresultatet för Hb var därmed stabilt under förhållandena i denna studie. För LPK och TPK förekom statistiskt signifikanta skillnader mellan resultatet vid den initiala analysen jämfört med efter fyra respektive sex timmar. Analysresultaten för LPK och TPK var därmed inte lika stabila som Hb är under förhållandena i studien. Den statistiska skillnaden bedömdes däremot inte ha någon klinisk betydelse, vilket ledde till slutsatsen är att kapillära prover för analys av Hb, LPK och TPK är hållbara i sex timmar vid förvaring i rumstemperatur. / One important factor in clinical practice is understanding the stability of analytes and for how long blood samples can be stored before analysis. Most published studies are based on venous blood samples rather than capillary. The knowledge about storage time for cells in capillary blood is therefore limited. Plenty of information can be obtained by analysing the blood cells and its components, including haemoglobin, white blood cells and platelets. These analyses are therefore some of the most common in clinical practice. The aim of this study was to evaluate the effect of the analysis result for haemoglobin, white blood cells and platelets in capillary blood samples after storage at room temperature for four and six hours, respectively. In the study, 100 capillary samples from anonymous patients were analysed with the haematology analyser Sysmex XN-10. The method for analysing haemoglobin was the sodium lauryl sulphate (SLS) detection method with spectrophotometry. White blood cells were analysed with fluorescens flow cytometry. Platelets were analysed with either impedance or fluorescens flow cytometry. The result of the study showed no statistically significant difference between the initial analysis results in haemoglobin and at four and six hours, concluding that within the conditions of this study, the analysis result for haemoglobin was stable. Significant statical differences were identified for both white blood cells and platelet analysis results at four and six hours. However, the identified statistical significance was not esteemed to have any clinical relevance. In conclusion haemoglobin, white blood cells and platelets in capillary blood can be stored for at least six hours at room temperature.

Umbilical cord blood (UCB) is used as a source of haematopoietic stem cells (HSCs) for transplantation but shows defective homing to the bone marrow niche and delayed haematological reconstitution. Following transplantation, HSCs will home to the bone marrow in response to the CXCL12 chemokine, adhere to the bone marrow sinusoidal endothelial cells and then migrate into and lodge in bone marrow niches. In addition to CXCR4, a variety of molecules have been described as being important in these processes. In this laboratory, junctional adhesion molecule-A (JAM-A) was shown to be expressed on human UCB CD133⁺/CD34⁺ cells and regulated by hypoxia. In this thesis, further phenotypic studies show that this molecule is most highly expressed on human CD41a⁺ megakaryocytes and CD14⁺ monocytes/macrophages in UCB. JAM-A was also found to be expressed on all human UCB CD133⁺ cells, which have been shown by others to encompass the HSCs and early myeloid-lymphoid precursors and on the majority of CD34⁺ haematopoietic progenitor cells (HPCs). While it is also present on bone marrow sinusoidal endothelium (BMEC), JAM-A is not detected on cultured bone marrow mesenchymal stromal cells (MSCs). JAM-A blockade, silencing and overexpression experiments showed that JAM-A contributes to, but is not solely responsible for, the adhesion of CD34⁺ haematopoietic progenitor cells to IL-1β activated BMEC-60 cells and fibronectin. Lack of significance in cell migration suggested that JAM-A is more likely to act as an adhesion molecule or a regulator of adhesion rather than as a migratory molecule in such cells. Further functional studies using the proximity ligation assay highlight a potential association of JAM-A with CXCR4 and the adhesion molecules, tetraspanin CD82 and integrin β1. Mechanistic studies were commenced to establish if JAMA could modulate CXCR4 signalling following CXCL12 stimulation, but time constraints prevented these from being completed. These preliminary experiments which were carried out first in the Jurkat cell line lacking JAM-A or transduced to express JAM-A, however, suggest that JAM-A may modulate CXCL12-induced Rap1 phosphorylation and ERK1/2 phosphorylation. The former pathway is important for integrin function and the latter pathway is important in cell adhesion. The results described here, although requiring finalisation, support the hypothesis that JAM-A acts as an adhesion molecule and also may fine tune CXCR4 and integrin mediated functions on human CD34⁺ cells, thereby potentially regulating engraftment of these cells to the bone marrow niche.

<p>UVOD: Tuberkuloza je odavno poznata bolest koja i danas u 21. veku jo&scaron; uvek predstavlja veliki javnozdravstveni problem, uprkos primeni moćnih antituberkuloznih lekova. Trećina svetske populacije inficirana je bacilom tuberkuloze. Svake godine oboli oko osam miliona, a umre oko dva miliona ljudi, zbog čega je tuberkuloza i dalje infektivno oboljenje sa najvećom stopom smrtnosti. Kasna dijagnoza, multirezistentna tuberkuloza i udruženost sa HIV infekcijom predstavljaju jednu od najvećih prepreka za efikasnu kontrolu ove bolesti u svetu. Rano otkrivanje se oslanja na kvalitetnu bakteriolo&scaron;ku dijagnostiku koja je kamen temeljac svakog nacionalnog programa za kontrolu tuberkuloze. Brza i tačna mikrobiolo&scaron;ka dijagnostika predstavlja osnovu programa kontrole tuberkuloze i zbog toga je uvođenje novih i brzih laboratorijskih testova od veoma velikog značaja. Razvijen je novi komercijalno dostupni imunohromatografski test koji se zasniva na detekciji antigena MPT64 glavnog sekretovanog proteina M. tuberculosis. Test je brz i pouzdan u identifikaciji izolovanih sojeva M. tuberculosis i jeftiniji je od konvencionalnih biohemijskih i molekularnih testova. CILJ: Ciljevi istraživanja su bili da se evaluiraju karakteristike novog brzog imunohromatografskog testa u identifikaciji mikobakterija izolovanih iz respiratornih uzoraka bolesnika sa tuberkulozom pluća i referentnih sojeva klinički značajnih vrsta netuberkuloznih mikobakterija (NTM). MATERIJAL I METODE: Istraživanje je sprovedeno u periodu od 1.1.2010. do 31.12.2013. i obuhvatilo je 43563 respiratornih uzoraka dobijenih od bolesnika hospitalizovanih u Institutu za plućne bolesti Vojvodine. Iz obrađenih respiratornih uzoraka izolovano je 3469 izolata mikobakterija. Identifikacija do nivoa vrste urađena je primenom standardnih biohemijskih testova, molekularnog testa (GenoType&reg; Mycobacterium) i imunohromatografskog testa (BDMGIT Tbc). U istraživanje je uključeno 100 sojeva Gram pozitivnih i Gram negativnih bakterija (n = 19 vrsta) izolovanih iz respiratornih kliničkih uzoraka. Identifikacija do nivoa vrste je potvrđena komercijalnim identifikacionim sistemima. REZULTATI: U toku četvorogodi&scaron;njeg istraživanja izolovano je 3469 izolata mikobakterija iz respiratornih uzoraka. U ispitivanom periodu ne postoji opadajući trend izolacije mikobakterija &scaron;to potvrđuje i koeficijent korelacije (r = 0,31). Svi izolati mikobakterija su identifikovani konvencionalnim biohemijskim ispitivanjima koja pokazuju da je 89% od svih izolata identifikovano kao Mycobacterium tuberculosis (M. tuberculosis), a 11% izolata kao NTM. Mycobacterium xenopi je bila najzastupljenija NTM vrsta identifikovana kod 55,3% izolata. Nakon biohemijske identifikacije kod 300 izolata M. tuberculosis i 100 izolata NTM, identifikacija je potvrđena komercijalno dostupnim molekularnim i imunohromatografskim testom. Na osnovu rezultata testiranja mikobakterija imunohromatografskim testom, senzitivnost, specifičnost, pozitivne i negativne prediktivne vrednosti bile su: 99,7%, 100%, 100% i 99%. U poređenju imunohromatografskog testa sa konvencionalnim biohemijskim ispitivanjima nije nađena statistički značajna razlika (p&gt; 0,5). Kappa vrednost testa je iznosila 0,993, a interval poverenja CI =0,98 &ndash; 1,00. U poređenju imunohromatografskog sa molekularnim testom vrednost kappa je iznosila 0,993, a interval poverenja CI = 0,98 &ndash; 1,00. Slaganje rezultata je potvrđeno i McNemar testom sa vredno&scaron;ću 0,99. Utvrđena je stabilnost sekretovanog antigena MPT64 i posle 5 godina od prvog testiranja. ZAKLJUČAK: Visoka senzitivnost i specifičnost imunohromatografskog testa omogućuju tačnu i preciznu identifikaciju M. tuberculosis kao i pouzdanu diferencijaciju M.tuberculosis od NTM &ndash; a. Imunohromatografski test može da predstavlja zamenu za konvencionalne biohemijske i molekularne testove u identifikaciji M. tuberculosis. Jeftiniji je, jednostavniji za izvođenje i brže se dobijaju rezultati čime seskraćuje vreme za postavljanje dijagnoze.</p> / <p>INTRODUCTION: Tuberculosis (TB) has been known as a disease for a long time, but nevertheless it represents a major public health issue even nowadays in the 21st century, despite potent antituberculous drugs applied. One third of the world population is infected by the TB bacillus. About eight million people get infected and two million die of tuberculosis in a year, so tuberculosis is still an infectious disease with the greatest mortality rate. Late diagnosis, multiresistant tuberculosis and concomitant HIV infection interfere mostly with an efficient control of the disease all over the world. Early TB detection largely depends on the high-quality bacteriological diagnostics, which is the corner stone of each national TB control programme. A fast and accurate microbiological TB diagnosis plays a crucial role in any TB control programme. It is therefore very important to introduce new and fast laboratory tests. A novel commercially available immunochromatographic test has been designed, based on the MPT64 antigen of the major M. tuberculosis &ndash; secreted protein. This is a rapid and reliable test to identify the isolated strains of M. tuberculosis, which is not expensive as conventional biochemical and molecular tests. OBJECTIVE: The objective of the investigation was to evaluate the new immunochromatographic rapid test to identify mycobacteria isolated from respiratory samples from pulmonary TB patients, and referential strains of clinically relevant species of nontuberculous mycobacteria (NTM). MATERIAL AND METHODS: The research was carried out in the period from 1st January, 2010 to 31st December, 2013. It included 43 563 respiratory samples obtained from the patients hospitalized in the Institute for Pulmonary Diseases of Vojvodina, Sremska Kamenica (Serbia). There were 3 469 mycobacterial isolates obtained from the processed respiratory samples. The species &ndash; level identification was performed by standard biochemical tests, the molecular test (GenoType&reg;Mycobacterium), and the immunochromatographic test (BD MGIT Tbc). The study included one hundred (100) of Gram positive and Gram negative bacteria (n = 19 species) isolated from respiratory clinical samples. The species &ndash; level identification was confirmed by commercial identification systems. RESULTS: During the four &ndash; year investigation, 3 469 mycobacterial isolates were obtained from respiratory samples. No declining tendency of mycobacterial isolation was registered in the examined period, as confirmed by the correlation coefficient (r = 0.31). All mycobacterial isolates were identified by conventional biochemical tests showing that 89% of all isolates were identified as M. tuberculosis, and 11% of the isolates as NTM. Mycobacterium xenopi was the most common NTM species identified in 55.3% of the isolates. Following the biochemical identification in 300 M. tuberculosis isolates and 100 NTM isolates, the identification was confirmed by commercially available molecular and immunochromatographic tests. Based on immunochromatographic testing of mycobacteria, the sensitivity, specificity, positive and negative predictive values of the test were 99.7%, 100%, 100% and 99% respectively. There is no statistically significant difference (p&gt; 0.5) when comparing features of immunochromatographic test with conventional biochemical assay. The kappa test value was 0.993, and the confidence interval CI = 0.98 &ndash; 1.00. Comparing the immunochromatographic with the molecular test, the kappa value was 0.993, and the confidence interval CI = 0.98 &ndash; 1.00. The congruence of the tests findings was also confirmed by the McNemar test, estimated to 0.99. The stability of the secreted MPT64 antigen was registered even five years after the first testing episode. CONCLUSION: The high sensitivity and specificity of the imunochromatographic test enable an accurate and precise identification of M. tuberculosis, as well as a reliable differentiation of M. tuberculosis from NTM. The immunochromatographic test may substitute conventional biochemical and molecular tests to identify M. tuberculosis. It is easier to perform and provides faster test results, thus reducing the time of establishing the diagnosis.</p>

The central problem for researchers of HIV-1 evolution is explaining the apparent design of the virus for causing pandemic infection in humans: understanding how HIV-1 spreads is key to halting the pandemic. Current knowledge of how HIV-1 spreads from host to host is based upon experimental observation and indirect inferences informed by theory. The hypothesis of this thesis is that diversity of HIV-1 around the time of transmission is important for viral adaptation to a new human host, rather than intrinsic superiority of particular strains found in infectious fluids from human donor hosts, and that studying recombination is important for understanding this behaviour. To demonstrate the apparent randomness of transmission, I test the null-hypothesis that hard selection accounts for between-host viral divergence in a rare case study of contemporaneous infection. I explain how the experimental data that I have generated and the analyses I have carried out address certain basic assumptions and predictions about HIV-1 transmission and may inform current strategies for vaccine design. Specifically, my approach contributes to the current literature on HIV-1, by investigating an alternative hypothesis to the single virion theory of sexual transmission and by characterizing the role of recombination in a pseudodiploid virus following multiple-infection.

The Lon protease is a mitochondrial matrix quality-control protease belonging to the family of AAA+ proteins (ATPases associated with many cellular activities). We had previously found Lon to be upregulated in lung tumours with a non-angiogenic phenotype in a microarray study comparing these to conventional angiogenic tumours. In this project I set out to investigate whether Lon had any role in modulating the hypoxic response of tumour cells. Using a novel monoclonal antibody against Lon, I found that upregulation of Lon was present in breast and lung tumours and that higher levels of Lon are correlated with shorter overall survival in breast cancer patients. Targeting Lon with siRNA and shRNA in tumour cell lines reduced the normoxic and hypoxic stabilisation of HIF-α subunits. This is mediated through a mechanism independent of the activity of HIF-prolyl hydroxylases and independent of any changes in mitochondrial transcription. I found that the pre-imported form of Lon could bind and chaperone VHL in the cytoplasm potentially modulating VHL activity. In cell lines and human tumours, I observed that the proline-hydroxylated form of HIF-1α is induced by hypoxia and the hydroxylated form of HIF-1α is associated with shorter overall survival in breast cancer patients. This observation supports the notion that higher levels of Lon is associated with poor survival by downregulating VHL leading to higher levels of hydroxylated HIF. Finally I show that targeting Lon in cell lines is able to inhibit growth in a cell-line dependent fashion and partially reverses the Warburg effect, increasing oxygen consumption and reducing lactate production. In conclusion, I have demonstrated the broad therapeutic potential of targeting the Lon protease in tumours and highlighted a mechanism of post-hydroxylation HIF-regulation that has not been previously recognised in VHL competent tumours.

Multipotent haematopoietic stem cells (HSCs) supply the organism with mature blood cells of all lineages throughout adult life. These cells first originate in the dorsal aorta (DA) of the vertebrate embryo, and a multitude of signalling pathways regulate their specification in the embryo. The emergence of HSCs is dependent on appropriate arterial specification and vessel maturation, processes which are heavily dependent on Notch signalling. This arterial involvement of Notch obscures its later roles in HSC specification. The Notch ligand dll4 is crucially involved in arterial development in the mammalian embryo, while zebrafish embryos deficient for dll4 activity only exhibit minor arterial defects at the time of HSC emergence. Here, the zebrafish model has been exploited to reveal the first specific evidence for a role of dll4 in HSC specification. Dll4 is required for the expression of runx1, a transcription factor (TF) required for HSC specification, prior to any observed effects on vascular development. HSCs and all their derivatives are depleted in dll4 morphants. To disentangle the genetic requlatory cascade downstream of dll4 and upstream of runx1, RNA-seq was employed to discover downstream effectors of this signalling. Expression and functional screening of best candidate genes revealed seven genes with novel roles in HSC development. Foxc1b is a dll4 target predominantly mirroring the dll4 phenotype, and is thus likely to be the downstream effector of dll4, upstream of runx1. Interestingly, foxc1b also has a later dll4-independent role in HSC development, remarkably similar to that of cmyb. Taken together I show here for the first time a requirement of dll4 upstream of runx1 in HSC specification, mediated by foxc1b, followed by a later dll4-independent phase in HSC development.

O Laboratório de Análises Clínicas (LAC) vem buscando, no decorrer dos anos, alternativas quanto à sua capacidade em gerar receita. A busca por melhores resultados incrementou a parceria com as organizações chamadas de \"convênios médicos\" ou \"medicina de grupo\" que, em geral, remuneram as análises laboratoriais com base em tabelas de procedimentos criadas pela Associação Médica Brasileira AMB. Destas, a mais utilizada é a Tabela AMB 92, devido a utilizar valores de Coeficiente de Honorários (CH), que convertidos em reais, são mais interessantes para os LAC. Este estudo teve como base o método recomendado pelo \"National Committee for Clinical Laboratory Standards\" - NCCLS, que normatiza a apuração do custo baseado na atividade desempenhada durante a sua realização. O objetivo deste trabalho foi estabelecer o custo das análises laboratoriais e verificar se, em comparação à tabela AMB 92, a opção pelos contratos com os \"convênios médicos\" realmente gera lucro a um laboratório de pequeno porte. Para tanto foram selecionadas as análises mais solicitadas no mês de agosto de 2004 em um laboratório de pequeno porte, que presta atendimento a pacientes conveniados a planos de saúde e particulares. O ressarcimento aos laboratórios prestadores de serviço é efetuado com base no valor do CH, que pode variar de acordo com o contrato firmado com os convênios médicos. Os resultados mostraram que na comparação dos custos unitários das 69 análises apuradas com a Tabela AMB-92 houve lucro em 52% das análises quando o valor de CH foi de R$ 0,2610 e quando atribuído um valor de CH de R$ 0,1800, houve lucro em apenas 28% das análises. / The Clinical Laboratory (CL) has been seeking, throughout these years, alternative forms of increasing budget. The search for better results has flourished partnerships with organizations named \"prepaid group practice\" or \"group medicine\" which usually reward the clinical analysis based on tables of procedures established by the Brazilian Medicai Association - BMA. Among them, the most employed is the BMA 92 Table, due to the use of payment coefficient values (PC) which, expressed in Brazilian currency (reais), are in CLs interests. This study was carried out based on the method recommended by the National Committee for Clinical Laboratory Standards - NCCLS, who draws up the regulation of the cost estimate of a procedure while it is carried out. The objective of this study was to establish the cost of clinical analysis and to verify if, comparing to the BMA 92 Table, the contracts with prepaid group practices are actually profitable for a small size laboratory. In order to achieve it, most requested analysis during August 2004 in a small size laboratory which offers services to patients affiliated with prepaid health plans and private health plans. The payment to the laboratories which offer services is made regarding the PC values, which may change according to the contract with the health plans. The results demonstrated that in comparison to the cost of each one of 69 analysis verified according to the BMA 92 Table, 52% of the analysis were profitable when the PC value was R$ 0.2610 and for the PC value of R$ 0.1800 only 28% of the analysis were profitable.