The effect of biotin interference on the results of blood hormone assays.

Approximately 70% of medical decisions are made based on results of laboratory investigations. Immunochemical methods are used most commonly in routine laboratory diagnostics of endocrine disorders. Those methods are limited by susceptibility of the immunochemical reaction to various interferences. Interference may be caused by the presence of autologous antibodies, heterophilic antibodies, or paraproteins in the blood serum, by cross-reactions with similar reagents, haemolysis, significant lipidaemia, or hyperbilirubinaemia. Some recent reports have indicated a significant effect of biotin on the reliability of laboratory investigations. Biotin is a water-soluble vitamin belonging to the B group. It is present in popular dietary supplements - alone or as a component of multi-vitamin formulas - and it is advertised as a remedy to falling out and fragility of hair and nails. Due to its low molecular weight and a strong affinity to streptavidin, biotin is used in many immunochemical tests. Due to a strong and stable bond of streptavidin and biotin, analytical methods using the streptavidin (avidin)-biotin system are characterised by superior sensitivity, and they allow determination of very low levels of the tested substance in biological material. The presence of exogenous biotin in a sample may cause interference when using tests that utilise the streptavidin (avidin)-biotin system. Interference of biotin with immunochemical tests depends on several factors: the construction of the immunochemical test, the dose used by the patient, the biotin concentration in the sample, and most of all - the time from the last dose to the collection of biological material for laboratory testing. In this paper we present some practical recommendations and a procedure to be followed in the case of suspected interference of biotin in immunochemical assays, for clinicians and laboratory diagnosticians.

Milk-alkali syndrome (MAS) as a complication of the treatment of hypoparathyroidism - a case study.

Milk-alkali syndrome (MAS), characterized by renal failure, metabolic alkalosis and hypercalcemia, is a severe and life-threatening complication of the treatment of hypoparathyroidism. The clinical course is often sudden and is not preceded by any prodromal symptoms. Occurrence does not depend on the duration of hypoparathyroidism treatment, although it is closely related to the applied therapy, especially the dose of calcium carbonate and active vitamin D preparations. Drugs influencing the glomerular filtration rate (angiotensin receptor blockers, sartans, aldosterone receptor antagonists, thiazide diuretics), lack of adequate routine control, changing the calcium carbonate supplementation, dehydration, a diet rich in pH-basic foods (i.e. vegetarian diet), pregnancy and other associated conditions are listed among the factors triggering MAS. A higher calcium carbonate dose is directly associated with an increased risk of milk-alkali syndrome. In case of a high calcium demand it is necessary to control renal function and monitor the level of calcium in the serum more frequently, aiming for the lower end of the reference range. If MAS has been confirmed or if there are alarming neurological symptoms suggestive of hypercalcemia, the patient must be sent to the hospital immediately. Treatment of MAS involves: discontinuation of calcium and vitamin D supplementation, and intravenous infusion of normal saline solution to eliminate volume deficiencies and to achieve forced diuresis while maintaining proper fluid balance. As soon as there is improvement in the patient's clinical condition, it is necessary to begin the treatment of comorbidities increasing the risk of renal failure or alkalosis (i.e. vomiting, diarrhea).

Severe selenium deficits in pregnant women irrespective of autoimmune thyroid disease in an area with marginal selenium intake.

OBJECTIVES: Selenium (Se) deficiency is related to an increased risk of preterm labor, miscarriage, preeclampsia, gestational diabetes, and other obstetric complications. As the Se status declines during pregnancy, we hypothesized that the decline may be exacerbated in women with autoimmune thyroid disease (AITD). MATERIAL AND METHODS: Pregnant women (n=74; 30 [23-38] years) were consecutively recruited from the district of Warsaw, Poland, and divided into healthy subjects (HS, n=45), and women with a diagnosis of AITD (AITD, n=29). Thyroglobulin antibodies (TG-aAb), thyroid peroxidase antibodies (TPO-aAb), TSH, free T3, free T4, total T3, and total T4, as well as urine iodine excretion were determined. Se status was assessed by serum Se and selenoprotein P (SELENOP) concentrations. Thyroid volume was evaluated by ultrasonography. RESULTS: Serum Se and SELENOP concentrations were relatively low in both control and AITD women. A Se deficit according to WHO definition (<45µg/l) was observed in 0%, 3.4%, 28.6% and 4.5%, 18.2%, 35.5% of women in the AITD and HS group, respectively, during the 1st, 2nd, and 3rd trimester. From first to third trimester, TPO-aAb and TG-aAb declined in AITD by 71% and 60%, respectively. The decline in TPO- and TG-aAb was unrelated to the Se status. CONCLUSIONS: In this area of habitual low Se intake, a high proportion of women developed a severe Se deficit during pregnancy, irrespective of AITD status. This decline must be considered as a preventable risk factor for pregnancy complications of relevance to both the unborn child and the pregnant mother.

Bone mineralization disorders as a complication of anorexia nervosa - etiology, prevalence, course and treatment. / Zaburzenia mineralizacji kosci jako powiklanie jadlowstretu psychicznego - etiologia, rozpowszechnienie, przebieg i leczenie.

Anorexia nervosa (AN) most often has its onset in adolescence, which is a crucial period to achieve peak bone mass. The hormonal abnormalities (hypoestrogenism, hypercortisolism, decreased secretion of dehydroepiandrosterone, testosterone, insulin-like growth factor) and malnutrition are associated with profound bone mineralization disorders. Densitomertic bone mineral density (BMD) values for osteopenia and osteoporosis were found respectively in 35-98% and 13-50% of women with AN. Prospective studies indicate a further decline in BMD at the beginning of treatment and a crucial importance of weight gain and return of spontaneous menses for its growth. Due to frequent chronic and relapsing course of AN densitometric assessment of BMD is recommended in all patients with AN and amenorrhea lasting around twelve months. In order to establish standards for the treatment of osteoporosis in AN, studies on pharmacological treatment are conducted. There are promising results indicating the improvement in BMD after treatment with physiologic oestrogen replacement treatment and sequential administration of medroxyprogesterone in teenage girls and bisphosphonates in adult women. Supplementation of vitamin D and adequate consumption of calcium from diet are recommended. Further studies on the effectiveness of long-term treatment of osteoporosis with regard to the possibility of increase in BMD and reducing the risk of osteoporotic fractures are needed.

Iodine supplementation during pregnancy of hypothyroid women treated with L-thyroxine neither influences neonatal TSH nor prevents decrease in maternal free thyroid hormone concentrations in second and third trimesters.

INTRODUCTION: Pregnant women require about 250 µg of iodine daily. Hypothyroid women treated with L-thyroxine do not utilise iodine, and metabolism of L-thyroxine tablets is an additional source of iodine for their foetuses. The aim of the study was to evaluate the influence of iodine supplementation in hypothyroid pregnant women treated with L-thyroxine on neonate TSH concentration and maternal thyroid parameters. MATERIAL AND METHODS: Ninety-two pregnant women with primary hypothyroidism on adequate thyroid hormone replacement were voluntarily divided into two groups: "thyroxine" (n = 38) treated with L-thyroxine only, and "thyroxine + iodine" (n = 54) treated additionally with 150 µg/day of iodine since 10th gestational week. Primary outcomes were the maternal thyroid function tests (TSH, fT4, fT3) and neonatal TSH concentrations at the 3-4th day of life. Urinary iodine concentration was measured at first and third trimester to compare iodine status in both groups. RESULTS: Iodine supplementation significantly increased median urinary ioduria in the third trimester (from 95.15 µg/L to 151.50 µg/L), but did not prevent the decrease of maternal fT4 and fT3 concentrations in the second and third trimester. Median neonate TSH concentration in both groups was within normal range, but was 33% higher in the "thyroxine + iodine" than in the "thyroxine" group (1.91 mU/L vs. 1.34 mU/L). Moreover, 8.77% of newborns in the "thyroxine + iodine" group had TSH > 5 mIU/L. CONCLUSIONS: We did not find evidence for a positive influence of iodine supplementation on thyroid function of either hypothyroid pregnant women sufficiently treated with L-thyroxine or their neonates. (Endokrynol Pol 2016; 67 (4): 367-374).

Vitamin D insufficiency in healthy pregnant women living in Warsaw.

BACKGROUND/OBJECTIVES: Ensuring the optimal level of 25-hydroxy-vitamin D (250HD) in serum (concentration above 30 ng/ml) is essential for protecting the health of the mother and the developing fetus. Vitamin D plays an important role in maintaining proper bone structure, preventing infections, reducing the risk of premature birth and gestational diabetes. The aim of the study was to verify whether healthy pregnant residents of Warsaw were deficient in vitamin D. MATERIAL AND METHODS: The material consisted of 150 serum samples of 50 healthy women in 1st, 2nd and 3rd trimester of pregnancy 72.7% of the sera were from women who reported taking multivitamin supplements containing vitamin D3 (71% out of that group was taking 400 IU daily). The concentration of 250HD was measured using the vitamin D total assay on Elecsys 2010 automatic analyzer (Roche Diagnostics). RESULTS: The average serum 250HD concentrations of 50 women in 1st, 2nd and 3rd trimester of pregnancy were respectively: 23.1 ng/ml, 24.8 ng/ml, and 25.1 ng/ml, with no statistically significant differences. The optimal levels of 250HD (30-80 ng/ml) were found in 30.0% of samples, hypovitaminosis (20-30 ng/ml) occurred in 38.7%, deficiency (10-20 ng/ml) in 24.0% and severe deficiency (less than 10 ng/ml) in 7.3% of cases. Mean concentration of 250HD in winter season (October 1 - March 31) was 23.6 ng/ml and in summer season (April 1 - September 30) was 25.5 ng/ml, with no statistically significant difference. On the basis of the BMI in 1st trimester two subgroups were distinguished from the studied subjects: BMI <21 (13 patients, 39 samples) and BMI >25 (14 patients, 42 samples). Mean 250HD concentration in these groups were 27.3 and 23.5 ng/ml respectively (p<0.05). High statistical significance (p<0.001) was found among the total number of samples with 250HD deficiency and severe deficiency (<20 ng/ml) and samples with hypovitaminosis and optimal 250HD level (>20 ng/ml) in these groups. CONCLUSIONS: Regardless of trimester and season, vitamin D below the optimal level is a common occurrence during pregnancy and the current level of supplementation among Polish pregnant women appears to be insufficient. Our data suggest that special attention should be paid to the problem of vitamin D insufficiency in overweight pregnant women.

[Iodine supply and thyroid function in the group of healthy pregnant women living in Warsaw]. / Zaopatrzenie wjod oraz czynnosc tarczycy w grupie zdrowych kobiet ciezarnych zamieszkujacych Warszawe.

UNLABELLED: Iodine deficiency and thyroid gland disorders are especially harmful for pregnant women and normal fetal development. After initiation in 1997 of obligatory iodine prophylaxis, Poland has been found since 2003 a country with sufficient delivery of this microelement. However, in the population of pregnant women, slight deficiency of this element still exists. Insufficient iodine supply results in abnormalities of thyroid hormones'biosynthesis. Simultaneously, adaptive changes, occurring in pregnancy, make the proper interpretation of hormone's assays difficult. Lack of normative data for the thyroid hormones concentration in the each pregnancy trimester for Polish population cause additional difficulties in the interpretation of these results. The aim of the study was prospective observation of iodine intake and thyroid function in healthy pregnant women supplemented with 150 pg of iodine daily MATERIALS AND METHODS: 62 healthy pregnant women living in Warsaw in the early weeks of pregnancy, confirmed by ultrasonographic examination, were included to this study. Pregnancies were singleton resulting in birth of healthy neonates. Urinary iodine concentrations (UIC), serum TSH, fT4, fT3, antyTPO, thyroid volume and morphology by the ultrasonography examination were assessed in consecutive trimesters of pregnancy. TSH level was measured in the each newborn. RESULTS: Low urinary iodine concentrations (UIC)-median 96 microg/l was found at the beginning of pregnancy Only in 14% of pregnant women UIC exceeded 150 microg/l. In spite of intended supplementation of at least 150 microg of extra iodine per day, medians of UIC in the next trimesters were 122 microg/l and 129 microg/l, respectively. TSH levels kept reference values for the 1st trimester of pregnancy in 86% of participants and in the next trimesters in 85% and 95%, respectively. Levels of fT4 were within reference range for the women in the 1st trimester. In 2nd trimester 12% and in 3rd trimester 33% of pregnant women had fT4 level below the reference value. Concentrations of fT3 were within reference values during whole pregnancy. Median thyroid volume was respectively 11.12 ml; 13.0 ml and 15.75 ml (range: 6.8-26.8 ml) in subsequent trimesters.Median neonatal' TSH level on the 3rd day of life, as a screening of thyroid insufficiency, was 1.34 mlU/l (range: 0.01-6.6 mlU/l) and in 4.41 % of newborns TSH concentrations were higher than 5 mlU/I. CONCLUSION: Despite the sufficient supply of iodine in the whole population, iodine consumption among the pregnant women is still not satisfactory. The increase of TSH values above the upper reference level for pregnant women in 15% of patients may be related to iodine deficiency. It is important to educate pregnancy planning women about this problem. Our observations confirm the importance of the recommendations that during the pregnancy every woman should receive supplementation of iodine at the minimal amount of 150 microg daily.