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Nuclear Medicine and Molecular Imaging Dec 2016The batch assay has been conventionally used for radioimmunoassay (RIA) because of its technical robustness and practical convenience. However, it has limitations in...
PURPOSE
The batch assay has been conventionally used for radioimmunoassay (RIA) because of its technical robustness and practical convenience. However, it has limitations in terms of the relative lag of report time due to the necessity of multiple assays in a small number of samples compared with the random assay technique. In this study, we aimed to verify whether the random assay technique can be applied in RIA and is feasible in daily practice.
METHODS
The coefficients of variation (CVs) of eight standard curves within a single kit were calculated in a CA-125 immunoradiometric assay (IRMA) for the reference of the practically ideal CV of the CA-125 kit. Ten standard curves of 10 kits from 2 prospectively collected lots (pLot) and 85 standard curves of 85 kits from 3 retrospectively collected lots (Lot) were obtained. Additionally, the raw measurement data of both 170 control references and 1123 patients' sera were collected retrospectively between December 2015 and January 2016. A standard curve of the first kit of each lot was used as a master standard curve for a random assay. The CVs of inter-kits were analyzed in each lot, respectively. All raw measurements were normalized by decay and radioactivity. The CA-125 values from control samples and patients' sera were compared using the original batch assay and random assay.
RESULTS
In standard curve analysis, the CVs of inter-kits in pLots and Lots were comparable to those within a single kit. The CVs from the random assay with normalization were similar to those from the batch assay in the control samples (CVs % of low/high concentration; Lot1 2.71/1.91, Lot2 2.35/1.83, Lot3 2.83/2.08 vs. Lot1 2.05/1.21, Lot2 1.66/1.48, Lot3 2.41/2.14). The ICCs between the batch assay and random assay using patients' sera were satisfactory (Lot1 1.00, Lot2 0.999, Lot3 1.00).
CONCLUSION
The random assay technique could be successfully applied to the conventional CA-125 IRMA kits. The random assay showed strong agreement with the batch assay. The random assay procedure could increase the flexibility and decrease the turnaround time of the radioimmunoassay technique.
PubMed: 27994689
DOI: 10.1007/s13139-016-0436-7 -
Postepy Dermatologii I Alergologii Dec 2014Acne and hirsutism are common manifestations of hyperandrogenism.
INTRODUCTION
Acne and hirsutism are common manifestations of hyperandrogenism.
AIM
To investigate whether or not acne is present in women with hirsutism, associated with different clinical, endocrine and ultrasonographic features.
MATERIAL AND METHODS
The prospective study included 135 women with hirsutism, aged 14-46 years. We measured the levels of hormones with radioimmunoassay/immunoradiometric assay methods.
RESULTS
Acne were present in 63 (47.6%) women with hirsutism. Sixty women had mild forms of acne, including: whiteheads, blackheads, papules and pustules. Only 3 women had moderate to severe acne, including nodules. In a group of women with hirsutism and acne, 6 (9.5%) were obese. In our study we found a high prevalence of androgen excess among hirsute women with acne: total testosterone was increased in 79%, free testosterone in 20.6%, androstenedione in 69.8%, dehydroepiandrosterone sulfate (DHEAS) in 30.1%, 17-OH-progesterone 68.2% and sex hormone-binding globulin (SHBG) was decreased in 33.3% of women. Women with hirsutism and acne have received oral contraceptives for a year, without or in a combination with other medication. Thirty-four (53.9%) women have shown improvement in hirsutism and acne.
CONCLUSIONS
In this study we found a high prevalence of acne in hirsute women. The prevalence of acne was higher in polycystic ovarian syndrome. Since these women have associated endocrine changes it is important to correct them with hormonal therapy.
PubMed: 25610349
DOI: 10.5114/pdia.2014.47118 -
Environmental Health Perspectives Oct 1987Human chorionic gonadotropin (hCG) is a glycoprotein hormone, secreted by the syncytiotrophoblast cells of the fertilized ovum, that enters the maternal circulation at... (Review)
Review
Human chorionic gonadotropin (hCG) is a glycoprotein hormone, secreted by the syncytiotrophoblast cells of the fertilized ovum, that enters the maternal circulation at the time of endometrial implantation. It is composed of two nonidentical subunits; alpha and beta, with molecular weights of 14 kD and 23 kD, respectively. Its alpha subunit is identical in primary structure to its glycoprotein homologs, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and thyroid-stimulating hormone (TSH). Human chorionic gonadotropin binds to the same receptor as hLH and displays the same biological response, namely, to stimulate the declining function of the corpus luteum to produce progestins and estrogen late in the menstrual cycle. The differences in the structures of hCG and hLH have been exploited to develop antibodies that can measure hCG specifically in the presence of hLH. Two-site antibody binding assays have been developed, based on a surface immunological concept of hCG epitopes, that involve four distinct regions to which antibodies against hCG can bind simultaneously. Antibody cooperative effects, in conjunction with kinetic advantages derived from the concentration factors by use of the sandwich assay technique (immunoradiometric assay, IRMA), have enabled development of extremely sensitive and specific measurement protocols for urinary hCG. The assay described herein permits the detection of pregnancy on an average 25.4 days after the first day of the preceding menses, as opposed to 29.5 days for conventional radioimmunoassay techniques. In addition, the greater sensitivity and specificity of this assay method has permitted the detection of episodes of fetal loss not detected by radioimmunoassay of urine specimens. A large scale epidemiological study is in progress using this assay technique as a way to identify pregnancies that are lost before becoming clinically apparent. This methodology provides a valuable tool for the determination of the rate of early fetal loss.
Topics: Amino Acid Sequence; Chorionic Gonadotropin; Female; Fetal Death; Humans; Immunoassay; Immunochemistry; Luteinizing Hormone; Molecular Sequence Data; Pregnancy
PubMed: 3319556
DOI: 10.1289/ehp.877457 -
Frontiers in Bioscience (Scholar... Jan 2010The parathyroid hormone-related peptide (PTHrP) has been shown to be the major pathogenic factor to humoral hypercalcemia of malignancy (HHM). The presence of PTHrP in... (Review)
Review
The parathyroid hormone-related peptide (PTHrP) has been shown to be the major pathogenic factor to humoral hypercalcemia of malignancy (HHM). The presence of PTHrP in many normal tissues and in normal or abnormal parathyroids has been described in literature and its role has been investigated. PTHrP release from parathyroid cells into the extracellular space has been demonstrated to depend on the extracellular calcium concentration. The hormone binds to PTH type 1 Receptor (PTH1R) with a high affinity, as well as parathyroid hormone (PTH). These hormones' amino-terminal (1-34) peptide fragments are considered sufficient to achieve efficient receptor activation and action on mineral ion homeostasis. Generally, diagnosis of primary hyperparathyroidism (PHPT) is based on hypercalcaemia and elevated levels of PTH. The advent of intact-PTH immunoradiometric assay allowed us to distinguish PHPT from non-parathyroid-dependent hypercalcaemia, but the presentation of normal PTH level and hypercalcaemia due to a parathyroid adenoma is possible. The aim of the study is to identify the relationship between the production of PTHrP without malignancy and the diagnosis of PHPT by a systematic review.
Topics: Calcium; Humans; Hypercalcemia; Hyperparathyroidism, Primary; Immunoradiometric Assay; Parathyroid Hormone-Related Protein; Receptor, Parathyroid Hormone, Type 1; Second Messenger Systems
PubMed: 20036948
DOI: 10.2741/s65 -
Annals of Laboratory Medicine Sep 2016Measurement of postoperative serum thyroglobulin (Tg) is important for detecting persistent or recurrent differentiated thyroid cancer. We evaluated the analytic...
BACKGROUND
Measurement of postoperative serum thyroglobulin (Tg) is important for detecting persistent or recurrent differentiated thyroid cancer. We evaluated the analytic performance of the DxI 800 assay (Beckman Coulter, USA) for serum Tg and anti-thyroglobulin antibodies (TgAbs) in comparison with that of the GAMMA-10 assay (Shinjin Medics Inc., Korea) for serum Tg and RIA-MAT 280 assay (Stratec, Germany) for TgAb.
METHODS
We prospectively collected blood samples from 99 patients thyroidectomized for thyroid cancer. The functional sensitivity was investigated in standards and human serum. Precision and linearity were evaluated according to the guidelines of the Clinical and Laboratory Standards Institute. The correlation between the two assays was assessed in samples with different Tg ranges.
RESULTS
The functional sensitivity of the DxI 800 assay for serum Tg was between 0.0313 and 0.0625 ng/mL. The total CV was 3.9-5.6% for serum Tg and 5.3-6.9% for serum TgAb. The coefficient of determination (R²) was 1.0 and 0.99 for serum Tg and TgAb, respectively. The cut-offs for serum TgAb were 4.0 IU/mL (DxI 800) and 60.0 IU/mL (RIA-MAT 280), and the overall agreement was 68.7%. The correlation between the two assays was excellent; the correlation coefficient was 0.99 and 0.88 for serum Tg and TgAb, respectively.
CONCLUSIONS
The DxI 800 is a sensitive assay for serum Tg and TgAb, and the results correlated well with those from the immunoradiometric assays (IRMA). This assay has several advantages over the IRMA and could be considered an alternative test for Tg measurement.
Topics: Autoantibodies; Humans; Immunoradiometric Assay; Luminescent Measurements; Prospective Studies; Reagent Kits, Diagnostic; Reproducibility of Results; Thyroglobulin; Thyroid Neoplasms
PubMed: 27374705
DOI: 10.3343/alm.2016.36.5.413 -
The Journal of Applied Laboratory... Mar 2017Growth differentiation factor 15 (GDF-15) can serve as a biomarker for cardiovascular disease burden and risk. We evaluated a new, fully automated...
BACKGROUND
Growth differentiation factor 15 (GDF-15) can serve as a biomarker for cardiovascular disease burden and risk. We evaluated a new, fully automated electrochemiluminescence immunoassay for measuring GDF-15.
METHODS
Six laboratories independently characterized the Elecsys® GDF-15 assay (Roche Diagnostics) under routine conditions. Within-run precision (repeatability), within-laboratory precision (intermediate precision), and between-laboratory precision (reproducibility) were assessed. Plasma-serum sample correlation, reagent lot-to-lot reproducibility, and instrument comparisons were performed. The Elecsys assay was compared to a research immunoradiometric assay (IRMA) and a commercially available ELISA. GDF-15 concentrations were measured with the Elecsys assay in 739 apparently healthy individuals.
RESULTS
CVs for within-run and within-laboratory precision ranged from 0.7% to 7.7% and 1.7% to 8.6%, respectively, for samples containing 670-16039 ng/L. CVs for between-laboratory precision ranged from 7.1% to 8.9% (766-14289 ng/L). Recovery of GDF-15 was comparable for serum, Li-heparin plasma, K2- and K3-EDTA plasma, and citrated plasma, between 2 reagent lots, and on the cobas e 411 and cobas e 601 analyzers (Roche Diagnostics). GDF-15 concentrations in the clinically relevant range (400-3000 ng/L) measured with the Elecsys assay showed a good correlation and agreement with those measured by IRMA or ELISA. GDF-15 concentrations in apparently healthy individuals increased with age but did not vary by sex.
CONCLUSIONS
The Elecsys GDF-15 assay demonstrates a robust analytic performance under routine conditions and provides an automated method for measuring GDF-15 concentrations in serum and plasma.
PubMed: 33379802
DOI: 10.1373/jalm.2016.022376 -
Journal of Korean Medical Science Dec 1989The sensitive and specific immunoradiometric assay is described for human proinsulin and its intermediate peptides (65-66 split and 32-33 split proinsulin). We developed...
The sensitive and specific immunoradiometric assay is described for human proinsulin and its intermediate peptides (65-66 split and 32-33 split proinsulin). We developed a monoclonal antibody-based two-site immunoradiometric assay with use of streptavidin-biotin labeling. The detection limits of the assays lie in the range of 0.5-2.0 pM. In the proinsulin assay proinsulin cross-reacted 66% with 65-66 split proinsulin but not with insulin or 32-33 split proinsulin. In the assay of 65-66 split proinsulin it does not cross-react with insulin, proinsulin or 32-33 split proinsulin. In the 32-33 split proinsulin assay it cross-reacted 84% with proinsulin and 60% with 65-66 split proinsulin. The precision (C.V.) of the assays was less than 15% over the various concentration. The mean concentrations of insulin, proinsulin, 65-66 split proinsulin and 32-33 proinsulin in eight young male subjects in the fasting state were (pM +/- S.E.M.) 20 +/- 3.6, 2.3 +/- 0.3, undetectable (less than 1.0) and 2.1 +/- 0.7 and at the maximum reached during an oral glucose tolerance test, 150 +/- 26, 9.9 +/- 1.4, 3.8 +/- 0.6 and 19.7 +/- 6.0 respectively.
Topics: Adult; Animals; Antibodies, Monoclonal; Bacterial Proteins; Biotin; Cross Reactions; Humans; Immunoradiometric Assay; Male; Mice; Proinsulin; Reproducibility of Results; Streptavidin
PubMed: 2639693
DOI: 10.3346/jkms.1989.4.4.171 -
Clinical Journal of the American... Jul 2014Alge et al. recently reported that urinary renin may be a prognostic biomarker for AKI after cardiac surgery. However, their urinary renin levels far exceeded published... (Comparative Study)
Comparative Study
BACKGROUND AND OBJECTIVES
Alge et al. recently reported that urinary renin may be a prognostic biomarker for AKI after cardiac surgery. However, their urinary renin levels far exceeded published plasma renin levels, whereas normally, urinary renin is <10% of plasma renin. This result raises questions about the specificity of the new Quantikine Renin ELISA Kit used in the work by Alge et al., which is claimed to detect total renin (i.e., renin and prorenin). Therefore, this study tested this assay.
DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS
Plasma and urine from 30 patients with hypertension, diabetes, or preeclampsia and 10 healthy pregnant women (randomly selected from sample sets obtained earlier to investigate urinary renin-angiotensin system components) were used to compare the ELISA with a validated renin immunoradiometric assay and an in-house enzyme kinetic assay. Measurements were performed before and after in vitro prorenin activation, representing renin and total renin, respectively.
RESULTS
Total renin measurements by ELISA, immunoradiometric assay, and enzyme kinetic assay were highly correlated. However, ELISA results were consistently ≥10-fold higher. The ELISA standard yielded low to undetectable levels in the immunoradiometric assay and enzyme kinetic assay, except after prorenin activation, when the results were ≥10-fold lower than the ELISA results. In plasma, prorenin activation increased ELISA results by 10%-15%. Urine contained no detectable prorenin.
CONCLUSIONS
The ELISA renin kit standard is prorenin, and its immunoreactivity and enzymatic activity after conversion to renin do not match the International Reference Preparation of human renin that has been used to validate previous immunoradiometric assays and enzyme kinetic assays; in fact, they are at least 10-fold lower, and thus, any measurements obtained with this ELISA kit yield levels that are at least 10-fold too high. The ELISA antibodies detect both renin and prorenin, with a preference for the former. Given these inconsistencies, urinary renin levels should be measured by established renin assays.
Topics: Adult; Aged; Biomarkers; Calibration; Case-Control Studies; Diabetic Nephropathies; Enzyme Precursors; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunoradiometric Assay; Kidney Diseases; Male; Middle Aged; Predictive Value of Tests; Pregnancy; Reagent Kits, Diagnostic; Reference Standards; Renin; Reproducibility of Results
PubMed: 24742480
DOI: 10.2215/CJN.12661213 -
The Quarterly Journal of Nuclear... Dec 2006The aim of this study is to investigate the diagnostic performance of serum chromogranin A (CgA) and plasma metanephrines (MN) assays in the diagnosis of... (Comparative Study)
Comparative Study
AIM
The aim of this study is to investigate the diagnostic performance of serum chromogranin A (CgA) and plasma metanephrines (MN) assays in the diagnosis of pheochromocytoma.
METHODS
We enrolled 44 patients affected by histologically proved adrenal pheochromocytoma. All patients underwent abdominal computed tomography and whole body 123I-MIBG scan to stage the disease. One hundred healthy blood donors and 148 patients affected by essential hypertension were enrolled as controls. Serum CgA and plasma MN were assayed by immunoradiometric assay (IRMA) and high-performance liquid chromatography. Cut-off levels were selected to obtain 99% specificity in healthy control subjects.
RESULTS
Both MN and CgA showed 95% sensitivity with comparable high specificity and diagnostic accuracy (96% and 96% for CgA, 94% and 95% for MN, respectively). By employing both markers and considering CgA or MN positivity, a 100% sensitivity was obtained with 95% accuracy. MN and CgA concentration clearly increased from controls to patients with pheochromocytomas (P<0.0001). A relationship between serum CgA (but not MN) and tumor mass was found (P<0.0001).
CONCLUSIONS
Both markers are sensitive and specific in chromaffin-tumors detection: CgA IRMA assay employed a simple and feasible technology and showed to be as sensitive and slightly more accurate than MN.
Topics: 3-Iodobenzylguanidine; Adrenal Gland Neoplasms; Adult; Aged; Biomarkers, Tumor; Chromogranin A; Female; Humans; Immunoradiometric Assay; Male; Metanephrine; Middle Aged; Neoplasm Proteins; Pheochromocytoma; Radiopharmaceuticals; Reproducibility of Results; Sensitivity and Specificity
PubMed: 17043632
DOI: No ID Found -
Indian Journal of Endocrinology and... Mar 2014Congenital hypothyroidism (CH) is one of the most common preventable causes of mental retardation in children and it occurs in approximately 1:2,000-1:4,000 newborns.
CONTEXT
Congenital hypothyroidism (CH) is one of the most common preventable causes of mental retardation in children and it occurs in approximately 1:2,000-1:4,000 newborns.
AIMS AND OBJECTIVES
The aim of this study is to determine the frequency of CH in neonates.
SETTINGS AND DESIGN
This cross-sectional study was conducted in neonatal units of the Department of Pediatrics Unit-I, King Edward Medical University/Mayo Hospital, Lahore and Lady Willington Hospital Lahore in 6 months (January-June 2011).
MATERIALS AND METHODS
Sample was collected by non-probability purposive sampling. After consent, 550 newborn were registered for the study. Demographic data and relevant history was recorded. After aseptic measures, 2-3 ml venous blood analyzed for thyroid-stimulating hormone (TSH) level by immunoradiometric assay. Treatment was started according to the individual merit as per protocol.
STATISTICAL ANALYSIS USED
Data was analyzed by SPSS 17 and Chi-square test was applied to find out the association of CH with different variables.
RESULTS
The study population consisted of 550 newborns. Among 550 newborns, 4 (0.8%) newborns had elevated TSH level. CH had statistically significant association with mother's hypothyroidism (P value 0.000) and mother's drug intake during the pregnancy period (P value 0.013).
CONCLUSION
CH is 0.8% in neonates. It has statistically significant association with mother's hypothyroidism and mother's drug intake during pregnancy.
PubMed: 24741519
DOI: 10.4103/2230-8210.129114