Influence of state-of-the-art laboratory techniques on the phenotyping of women with polycystic ovary syndrome in the clinical setting.

PURPOSE: Evidence-based guidelines for the management of polycystic ovary syndrome (PCOS) recommend clinical laboratories use liquid chromatography-tandem mass spectrometry (LC-MS/MS) for diagnosing biochemical hyperandrogenism. However, automated immunoassays are still mostly used in routine laboratories worldwide. Another hurdle for PCOS phenotyping in the clinical setting is ultrasound assessment of polycystic ovarian morphology. We address the impact of using state-of-the-art (LC-MS/MS) and of an anti-müllerian hormone (AMH) assay on the diagnosis of PCOS in routine practice. METHODS: In a cross-sectional study, we included 359 premenopausal women consecutively evaluated because of symptoms of functional androgen excess or hyperandrogenemia, and finally diagnosed with PCOS. Patients were submitted to routine phenotyping based on serum androgen measurements by immunoassays and an ovarian ultrasound when necessary. Samples of all patients were also assayed by LC-MS/MS for hyperandrogenemia and for circulating AMH. RESULTS: The observed agreement between immunoassays and LC-MS/MS in identifying hyperandrogenemia was poor [78.0%; k(95%CI): 0.366 (0.283;0.449)]. The observed agreement between ultrasound and increased AMH was 27.3% [(95%CI): 0.060 (0.005; 0.115)]. Using LC-MS/MS changed PCOS phenotypes in 60(15.8%) patients. Fifty-two (18.3%) individuals with hyperandrogenemia by routine immunoassays no longer presented with androgen excess by LC-MS/MS. Overall diagnostic agreement between routine assessment using immunoassays and ultrasound and that derived from LC-MS/MS and the addition of AMH to US was moderate [weighted κ (linear weights): 0.512 (0.416;0.608)]. CONCLUSIONS: Immunoassays used in routine practice are unacceptably inaccurate for phenotyping women with PCOS. Our data cast some doubts upon the interchangeability of serum AMH and ultrasound examination for the diagnosis of PCOS.

Serum HMGB1 levels are independently associated with glucose clamp-derived measures of insulin resistance in women with PCOS.

PURPOSE: PCOS is associated with low grade inflammation which could play a role in insulin resistance and ovarian dysfunction. Preliminary findings suggested that serum levels of HMGB1, a cytokine involved in inflammation, might be altered in women with PCOS. Primary aim of this study was to assess whether HMGB1 serum concentrations are associated with PCOS and with the state of insulin resistance of these women. METHODS: Sixty women with PCOS, selected to have a similar proportion of subjects with altered or normal insulin sensitivity, and 29 healthy controls were studied. Serum HMGB1 levels were compared in subgroups of PCOS women and controls. In PCOS women, insulin sensitivity was assessed by the glucose clamp technique and HMGB1 was measured at baseline and after acute hyperinsulinemia. RESULTS: HMGB1 levels were similar in women with PCOS and controls and no elements used for diagnosing PCOS were associated with serum HMGB1. However, HMGB1 concentrations were higher in insulin-resistant vs insulin-sensitive PCOS women (p = 0.017), and inversely associated with insulin-induced total and non-oxidative glucose metabolism. In both subgroups of PCOS women, serum HMBG1 levels significantly increased after acute hyperinsulinemia. CONCLUSIONS: These data suggest that HMGB1 levels are not associated with PCOS per se, but with insulin resistance. Further research should establish the underlying nature of this relationship, and whether this protein might play a role in the metabolic complications of PCOS.

Body mass index and occupational accidents among health care workers in a large university hospital.

INTRODUCTION: Obesity is associated with a number of chronic diseases such as cardiovascular diseases and cancers. The association of obesity with occupational accidents has been suggested although the evidence is less convincing. The objective of the study is to analyse the relationship between BMI values and ergonomic accidents in a large University Hospital. METHODS: The relationship between body mass index (BMI) and the incidence of ergonomic occupational accidents over a period of 8 years was investigated in a cohort of employees of a large University Hospital, covering almost 27,000 person-years of observation. This relationship was stratified according to the variables age, gender, functional status within the organization and work schedule (part-time or full time). Height and weight were objectively measured, demographic data were obtained from the human resource department and the registration of ergonomic accidents was carried out by the safety and prevention department of the hospital. RESULTS: The number of ergonomic accidents, expressed as number/1000 person-years was higher for female employees compared to male employees, increased with age and markedly increased from functional class A (leading or expert function and higher educational level) to D (executive function in patient care and technical department). However, the incidence of ergonomic accidents accompanied by loss of working time was not significantly associated with BMI, independently of age and gender. In addition, the type of accident and the severity of the accidents expressed as the number of days absent from work were unrelated to BMI. CONCLUSION: No independent relationship between BMI and the incidence of ergonomic accidents could be identified in our cohort. Tailoring working conditions to individual BMI levels is not recommended.

Role of sex hormone-binding globulin in the free hormone hypothesis and the relevance of free testosterone in androgen physiology.

According to the free hormone hypothesis, biological activity of a certain hormone is best reflected by free rather than total hormone concentrations. A crucial element in this theory is the presence of binding proteins, which function as gatekeepers for steroid action. For testosterone, tissue exposure is governed by a delicate equilibrium between free and total testosterone which is determined through interaction with the binding proteins sex hormone-binding globulin and albumin. Ageing, genetics and various pathological conditions influence this equilibrium, hereby possibly modulating hormonal exposure to the target tissues. Despite ongoing controversy on the subject, strong evidence from recent in vitro, in vivo and human experiments emphasizes the relevance of free testosterone. Currently, however, clinical possibilities for free hormone diagnostics are limited. Direct immunoassays are inaccurate, while gold standard liquid chromatography with tandem mass spectrometry (LC-MS/MS) coupled equilibrium dialysis is not available for clinical routine. Calculation models for free testosterone, despite intrinsic limitations, provide a suitable alternative, of which the Vermeulen calculator is currently the preferred method. Calculated free testosterone is indeed associated with bone health, frailty and other clinical endpoints. Moreover, the added value of free testosterone in the clinical diagnosis of male hypogonadism is clearly evident. In suspected hypogonadal men in whom borderline low total testosterone and/or altered sex hormone-binding globulin levels are detected, the determination of free testosterone avoids under- and overdiagnosis, facilitating adequate prescription of hormonal replacement therapy. As such, free testosterone should be integrated as a standard biochemical parameter, on top of total testosterone, in the diagnostic workflow of male hypogonadism.

Correlation between saliva and serum concentrations of estradiol in women undergoing ovarian hyperstimulation with gonadotropins for IVF/ICSI.

AIM OF THE STUDY: To examine saliva- and serum concentrations correlation of estradiol (E2) in women undergoing ovarian hyperstimulation for IVF/ICSI. Saliva measurements could simplify stimulation follow up. A 'home' test for E2 could be useful. METHODS: Prospective interventional academic monocentric study at the Centre for Reproductive Medicine of the University Hospital of Ghent, Belgium. Between November 2014 and August 2015 thirty-one patients were included after random selection (inclusion criteria: < 41 years of age, any rank of IVF/ICSI cycle, serum anti- Müllerian hormone concentration ≥ 1 µg/L, treatment completely at the University Hospital.) Measurements took place using immunoassay serum measurements. Estradiol was determined in saliva and serum by LC-MS/MS. At every control, E2 was measured in saliva and serum. Equilibrium analysis on a part of the serum samples took place. Statistic method used is a linear Mixed- Effects model (MIXED) in SPSS. RESULTS: Statistical analysis shows a strong linear relation between serum and salivary E2, (R2 of 0.75). E2 in equilibrium dialysis and E2 in serum were also strong correlated (R2 of 0.85). CONCLUSIONS: Strong correlation between serum and salivary E2 concentrations was found. Equilibrium dialysis showed good correlation with salivary E2. Saliva can be a good surrogate for free E2 in women undergoing ovarian hyperstimulation. This may create an opportunity to develop a point of care test for measuring E2, in purpose to simplify screening for OHSS risk.

Hair cortisol in relation to job stress and depressive symptoms.

BACKGROUND: Measurement of hair cortisol concentration (HCC) may be used as a biomarker for chronic stress. However, the association between stress and HCC has rarely been investigated in a working population. AIMS: To explore associations between (i) HCC and various stress measures and (ii) HCC and symptoms of depression in Belgian workers. METHODS: Hair samples were collected from workers in two production companies and cortisol content was determined by liquid chromatography tandem mass spectrometry. Participants completed a questionnaire including socio-demographics, health behaviours and standardized measures for assessing stress. RESULTS: After excluding those workers suffering from a psychiatric or neuroendocrine disease and those treated with glucocorticoids, there were a total of 102 workers with both questionnaire, cortisol results and anthropometric measures. Median HCC was 5.73 pg/mg hair (interquartile range = 4.52-9.06). No significant associations were found between cortisol and the standardized measures related to several work psychosocial risk factors. A significantly lower mean HCC was found in shift workers compared with dayworkers, adjusted for age. Additionally, a significant higher mean HCC was found in workers with symptoms of depression compared with those without symptoms of depression, after adjustment for age. CONCLUSIONS: HCC showed a limited applicability as a biomarker for job stress in this sample, although the results suggest this method may be a suitable marker for detecting early symptoms of depression. Further research is needed to investigate the applicability of HCC in the working environment and within job stress research.

Calcium and bone homeostasis in heterozygous carriers of CYP24A1 mutations: A cross-sectional study.

BACKGROUND: Bi-allelic CYP24A1 mutations can cause idiopathic infantile hypercalcemia (IIH), adult-onset nephrocalcinosis, and possibly bone metabolism disturbances. It is currently unclear if heterozygous carriers experience clinical problems or biochemical abnormalities. Our objective is to gain insight in the biochemical profile and health problems in CYP24A1 heterozygotes. STUDY DESIGN: Cross-sectional evaluation of participants. Data of previously reported carriers are reviewed. SETTING AND PARTICIPANTS: Outpatient clinic of a tertiary care hospital. Participants were eight family members of an infant with a well-characterized homozygous CYP24A1 mutation c.1186C>T p.(Arg396Trp). OUTCOMES: Serum vitamin D metabolites. Symptoms or biochemical signs of hypercalcemia, hypercalciuria or nephrocalcinosis. Bone health in heterozygous as compared to wild type (WT) subjects. MEASUREMENTS: Genotyping by Sanger sequencing; vitamin D metabolites by liquid chromatography tandem mass spectrometry; renal, calcium and bone markers by biochemical analyses; presence of nephrocalcinosis by renal ultrasound; bone health by dual-energy X-ray absorptiometry and peripheral quantitative computed tomography. RESULTS: Six participants were heterozygous carriers of the mutation. None of the heterozygous subjects had experienced IIH. One had a documented history of nephrolithiasis, two others had complaints compatible with this diagnosis. No major differences between WT and heterozygous subjects were found regarding bone health, serum or urinary calcium or 25OHD/24,25(OH)2D ratio. Literature reports on three out of 33 heterozygous cases suffering from IIH. In all three, the 25OHD/24,25(OH)2D ratio was highly elevated. Nephrocalcinosis was frequently reported in family members of IIH cases. LIMITATIONS: Small sample size, lack of a large control group. CONCLUSIONS: Our and literature data suggest that most heterozygous CYP24A1 mutation carriers have a normal 25OHD/24,25(OH)2D ratio, are usually asymptomatic and have a normal skeletal status but may possibly be at increased risk of nephrocalcinosis. A review of the available literature suggests that an elevated 25OHD/24,25(OH)2D ratio may be associated with symptoms of IHH, irrespective of carrier status.

Relation of adrenal-derived steroids with bone maturation, mineral density and geometry in healthy prepubertal and early pubertal boys.

BACKGROUND: Little is known about the effects of adrenal steroids on skeletal maturation and bone mass acquisition in healthy prepubertal boys. OBJECTIVE: To study whether adrenal-derived steroids within the physiological range are associated with skeletal maturation, areal and volumetric bone mineral density (aBMD and vBMD) and bone geometry in healthy prepubertal and early pubertal boys. METHODS: 98 healthy prepubertal and early pubertal boys (aged 6-14 y) were studied cross-sectionally. Androstenedione (A) and estrone (E1) were determined by liquid chromatography tandem mass spectrometry and DHEAS was determined by immunoassay. Whole body and lumbar spine aBMD and bone area were determined by dual-energy X-ray absorptiometry. Trabecular (distal site) and cortical (proximal site) vBMD and bone geometry were assessed at the non-dominant forearm and leg using peripheral QCT. Skeletal age was determined by X-ray of the left hand. RESULTS: Adrenal-derived steroids (DHEAS, A and E1) are positively associated with bone age in prepubertal and early pubertal children, independently of age. There are no associations between the adrenal-derived steroids and the studied parameters of bone size (lumbar spine and whole body bone area, trabecular or cortical area at the radius or tibia, periosteal circumference and cortical thickness at the radius or tibia) or BMD (aBMD or vBMD). CONCLUSION: In healthy prepubertal and early pubertal boys, serum adrenal-derived steroid levels, are associated with skeletal maturation, independently of age, but not with bone size or (v)BMD. Our data suggest that adrenal derived steroids are not implicated in the accretion of bone mass before puberty in boys.

Sex steroids in relation to sexual and skeletal maturation in obese male adolescents.

BACKGROUND: Childhood obesity is associated with an accelerated skeletal maturation. However, data concerning pubertal development and sex steroid levels in obese adolescents are scarce and contrasting. OBJECTIVES: To study sex steroids in relation to sexual and skeletal maturation and to serum prostate specific antigen (PSA), as a marker of androgen activity, in obese boys from early to late adolescence. METHODS: Ninety obese boys (aged 10-19 y) at the start of a residential obesity treatment program and 90 age-matched controls were studied cross-sectionally. Pubertal status was assessed according to the Tanner method. Skeletal age was determined by an x-ray of the left hand. Morning concentrations of total testosterone (TT) and estradiol (E2) were measured by liquid chromatography-tandem mass spectrometry, free T (FT) was measured by equilibrium dialysis, and LH, FSH, SHBG, and PSA were measured by immunoassays. RESULTS: Genital staging was comparable between the obese and nonobese groups, whereas skeletal bone advancement (mean, 1 y) was present in early and midadolescence in the obese males. Although both median SHBG and TT concentrations were significantly (P < .001) lower in obese subjects during mid and late puberty, median FT, LH, FSH, and PSA levels were comparable to those of controls. In contrast, serum E2 concentrations were significantly (P < .001) higher in the obese group at all pubertal stages. CONCLUSION: Obese boys have lower circulating SHBG and TT, but similar FT concentrations during mid and late puberty in parallel with a normal pubertal progression and serum PSA levels. Our data indicate that in obese boys, serum FT concentration is a better marker of androgen activity than TT. On the other hand, skeletal maturation and E2 were increased from the beginning of puberty, suggesting a significant contribution of hyperestrogenemia in the advancement of skeletal maturation in obese boys.

Associations of sex steroids with bone maturation, bone mineral density, bone geometry, and body composition: a cross-sectional study in healthy male adolescents.

BACKGROUND: Although both testosterone (T) and estradiol (E2) are considered essential in the regulation of the male skeleton, there are few data concerning the relative contribution of T and E2 on bone mineral density (BMD), bone geometry, and bone maturation in healthy boys. OBJECTIVE: The objective of the study was to analyze the relationship between T and E2 and BMD, bone geometry, skeletal maturation, and body composition. METHODS: This is a cross-sectional study in 199 healthy boys (aged 6-19 y). T and E2 were determined by liquid chromatography tandem mass spectrometry. Whole-body and lumbar areal bone mineral density (aBMD) and bone area, lean mass, and fat mass were determined by dual-energy X-ray absorptiometry. Trabecular (distal site) and cortical (proximal site) volumetric BMD (vBMD) and bone geometry were assessed at the nondominant forearm and leg using peripheral quantitative computed tomography. Skeletal age was determined by an X-ray of the left hand. RESULTS: T was positively associated with lean mass (P < .001), lumbar and whole-body bone area (P < .001), trabecular and cortical area (P < .01), and periosteal circumference (P < .01) at the radius. E2 was positively associated with lumbar and whole-body aBMD (P < .001), trabecular vBMD at the radius and tibia (P < .01), and cortical thickness at the radius (P < .05). E2 was an independent negative predictor of the endosteal circumference (P < .01). Moreover, E2 was positively associated with bone age advancement (P < .001). CONCLUSION: Circulating E2 is positively associated with bone maturation and aBMD and vBMD and negatively with endosteal circumference in healthy boys, whereas T is a determinant of lean mass and bone size. These findings underscore the important role of E2 in skeletal development in boys.

Effect of non-esterified fatty acids on bovine theca cell steroidogenesis and proliferation in vitro.

Elevated serum non-esterified fatty acid (NEFA) levels associated with a negative energy balance (NEB) may affect ovarian function and hence reproductive performance in high-yielding dairy cows. We have investigated the individual and combined effects of the three major NEFAs on bovine theca cell proliferation and steroidogenesis in vitro. Theca cells from healthy large follicles (>8 mm) obtained from slaughterhouse ovaries were cultured in serum free medium in the presence of 0, 50, 150 and 200 microM of palmitic acid (PA; C16:0); 0, 50, 150 and 250 microM of stearic acid (SA; C18:0); and/or 0, 50, 150 and 250 microM of oleic acid (OA; C18:1). Progesterone and androstenedione concentrations were measured in spent medium after 48 h of culture and cell numbers were determined spectrophotometrically per culture well. Cell viability was assessed by annexin-V FITC/propidium iodide staining. Only the treatment with 200 microM of PA inhibited cell proliferation (P<0.001) when tested individually, both of the mixtures tested (M1=100 microM of PA, 130 microM of SA and 140 microM of OA; M2=200 microM PA, 260 microM of SA and 280 microM of OA) reduced cell numbers (P<0.001). Progesterone and androstenedione production, both per well and per 10(4) cells, were not affected by any of the treatments, with the exception of M2. This mixture reduced progesterone production per well and per 10(4) cells (P<0.05). The effects observed were most likely caused by the cytotoxic action of the NEFAs, as demonstrated by the increased percentage of early apoptotic (M1) and late apoptotic/necrotic cells (M1 and M2) in the combination treatments (P<0.05). When combined, elevated physiological concentrations of PA, SA and OA can modulate theca cell proliferation and steroidogenesis in vitro by reducing theca cell viability. These NEFAs may be one of the mediators through which NEB compromises ovarian functioning and thus fertility in high-yielding dairy cows.

Validation of 5 routine assays for serum free testosterone with a candidate reference measurement procedure based on ultrafiltration and isotope dilution-gas chromatography-mass spectrometry.

BACKGROUND/METHOD: The analytical validity of free testosterone (FTe) analog immunoassays is subject to much controversy. We revisited the validation of 4 analog assays and 1 FTe calculation procedure with a metrologically traceable reference measurement procedure (RMP) based on ultrafiltration and isotope dilution-mass spectrometry for direct measurement of Te in the ultrafiltrate. To this end, we performed split-sample measurements of 40 male sera. RESULTS: Deming regression showed that 3 of the immunoassays had moderate to good correlation (0.8474 < or = r < or = 0.9241) with the RMP; however, the slope was markedly below 1. The FTe calculation procedure was in good agreement with this result. The Sy/x values for all assays were higher than the combined imprecision values, which indicate their susceptibility to matrix-related effects. CONCLUSIONS: The study demonstrated substantial differences in analytical quality of FTe assays; however, the results suggested that after extending the validation with a larger variety of samples, recalibration of some analog assays might be worth further investigation.

Recombinant humane thyrotropin (rhtSH) a new aid in the diagnosis and treatment of thyroid carcinoma with radio-iodine.

By example of two cases a newly available tool, the recombinant humane thyroid stimulating hormone (rhTSH) is discussed in its use as an adjunct in diagnosing and treating differentiated thyroid carcinoma with radio-iodine. This product is an easier and safe alternative to the necessary rise of TSH induced by thyroid hormone withdrawal and concurrent hypothyroidism. Although discrepancies in favour of the classical approach have been demonstrated in some patients, the clinical relevancy of these must be weighted against the advantage of avoiding undesirable symptoms and possible tumour growth by the use of rhTSH. The role of rhTSH in the follow-up diagnosis and radioiodine treatment of thyroid carcinoma will undoubtedly increase in importance.

Determination of user requirements for the secure communication of electronic medical record information.

Health professionals need to have accurate patient data in order to make the right diagnosis and to give an optimal treatment. In many cases, the 'medical' record, whether in electronic form or paper form is distributed over several health care providers and health care enterprises. Technically, there are several ways to provide access to remote record information or parts thereof. Legislation however puts restrictions on the communication of personal information in order to protect the privacy of the patient. This paper gives an overview of requirements and constraints when communicating electronic medical record information and summarises the findings of the SEMRIC project in determining requirements from a number of practical cases.

Development of the Logical Observation Identifier Names and Codes (LOINC) vocabulary.

The LOINC (Logical Observation Identifier Names and Codes) vocabulary is a set of more than 10,000 names and codes developed for use as observation identifiers in standardized messages exchanged between clinical computer systems. The goal of the study was to create universal names and codes for clinical observations that could be used by all clinical information systems. The LOINC names are structured to facilitate rapid matching, either automated or manual, between local vocabularies and the universal LOINC codes. If LOINC codes are used in clinical messages, each system participating in data exchange needs to match its local vocabulary to the standard vocabulary only once. This will reduce both the time and cost of implementing standardized interfaces. The history of the development of the LOINC vocabulary and the methodology used in its creation are described.

Evolution of the Intranet in the University Hospital of Gent.

The explosive development of the internet in recent years has lead to the production of massive collections of web-based tools and development know-how. Implementing an Intranet solution within a health care environment offers tremendous advantages for internal information management, distribution and collaborative computing. Easy adaptability, scalability and the low development cost allow easy integration into existing health care structures. A key aspect of the UZ Gent Intranet is its transparent interaction with the currently implemented HIS thus providing an open gateway to the future.

Automation of toxicological screenings on a Hewlett Packard Chemstation GC-MS system.

OBJECTIVES: To optimize the interpretation of GC-MS toxicological screenings (i.e., to facilitate ion specific queries, create custom reports specifically adapted to each confirmation procedure, and eliminate redundant and/or inaccurate data on library search reports). DESIGN AND METHODS: The MS Chemstation software of the Hewlett Packard 5972 is constructed in a modular way. We made extensive modifications to two modules, the data analysis and the report modules, using the built-in MS Chemstation macro language. RESULTS: Ion specific queries were automated for over 60 commonly encountered analytes. Custom reports were created for the confirmation of positive drugs-of-abuse immunoassay results. With the incorporation of decision support rules into the data processing and the reporting phases, we obtained sensitive, accurate, and concise reports. CONCLUSIONS: The MS Chemstation software can be tailored to the needs of each individual application. The incorporation of a rule-based decision support system enhances the quality of the GC-MS toxicological screenings and results in faster, easier, and more reliable processing.

The research in semantics behind the OpenLabs coding system.

The OpenLabs coding system is an established, comprehensive, dynamic, flexible, open, multilingual European system which is tailored to meet the electronic data interchange (EDI) needs of medical laboratory users. The OpenLabs coding system, having many specific, independent classes and considerable flexibility, serves two different objectives: (i) unambiguous coding of entities present in messages used for EDI in clinical pathology; and (ii) interfacing with other nomenclatures and coding schemes to map concepts between different systems.

Logical observation identifier names and codes (LOINC) database: a public use set of codes and names for electronic reporting of clinical laboratory test results.

Many laboratories use electronic message standards to transmit results to their clients. If all laboratories used the same "universal" set of test identifiers, electronic transmission of results would be greatly simplified. The Logical Observation Identifier Names and Codes (LOINC) database aims to be such a code system, covering at least 98% of the average laboratory's tests. The LOINC database should be of interest to hospitals, clinical laboratories, doctors' offices, state health departments, governmental healthcare providers, third-party payors, organizations involved in clinical trials, and quality assurance and utilization reviewers. The fifth release of the LOINC database, containing codes, names, and synonyms for approximately 6300 test observations, is now available on the Internet for public use. Here we describe the LOINC database, the methods used to produce it, and how it may be obtained.

Comparison of a recombinant thromboplastin with Thrombotest for oral anticoagulant control.

Thrombotest results expressed in international normalized ratio (INR) values, obtained in 108 patients on oral anticoagulant treatment, were compared with prothrombin time (PT) results with a recombinant thromboplastin. The former results were obtained on an Amelung coagulometer, the latter on a photo-optical instrument. Using the Thrombotest method, performed within 2 h after sampling as the reference method, a first group of 63 patients had an INR value between 2 and 4. This group was considered as adequately anticoagulated and served as a true positive population in further analysis. The remaining 45 patients (true-negative group) had an INR value below 2 or higher than 4 and could thus be considered as inadequately anticoagulated. Using these definitions, a sensitivity of 86% and a specificity of 96% could be calculated for the PT with the recombinant thromboplastin. All tests from patients on oral anticoagulant treatment were also performed after 24 h storage of the blood or plasma samples at room temperature. When we compared the reference Thrombotest results with those of the late Thrombotest and the late PT recombinant thromboplastin, sensitivities of 86 and 86% as well as specificities of 91 and 96% were found, respectively. In conclusion, PT with a recombinant thromboplastin on a photo-optical instrument, even after prolonged storage of the plasma samples at room temperature, can be considered as suitable for oral anticoagulation control.