• The Korean Journal of Nuclear Medicine
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• v.14 no.1
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• pp.9-16
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• 1980

A 2-site immunoradiometric assay for serum ferritin was evaluated with commercially available kit. The assay required 6 hours. The slope of the standard curve kept up ideal range with the calculation of maxium binding instead of total dose until expire date. The stage II washing was more important than the stage I washing on the modified washing procedure as the bead keeping to remain in the tube. With this modified mothod, three times of tube. washing was sufficient to reduce the significant errors The measured values of serially diluted sample with standard diluting buffer was proportional to the predicted values. In the experiment of serum effect on the assay. a linear relationship from 5 to 50% serum, but beyond 50% there was reduction in measured ferritin concentration. It has a sensitivity of 2.77 ng/ml, within-assay precision (CV) of 8.0%, and between-assay reproducibility(CV) of 7.4% (mean 174.8 ng/ml).

• Journal of Nutrition and Health
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• v.29 no.9
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• pp.971-980
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• 1996

The soluble transferrin receptor(TfR) in human serum has been shown recently to be a truncated form of intact membrane bound receptor containing most of the extracellular domain. We purfied the transferin-free TfR from human serum by immounoaffinity chromatography which produced the single protein identity in high resolution gel chormatography. The monoclonal antibodies(MAb) against purifed serum TfR were produced by fusion of spleen cells o fimmunized Balb/c mice and SP2 cells. Ten hybrids producing MAb specific for serum TfR were identifed and determine their iostypes. A immunoraddiometric assay (IRMA) for serum TfR was established using two monoclonal IgG1 antibodies as the coating and indicator antibodies on the bosis of their suitability in sandwich IRMA of serum TfR. The mean serum TfR levels in the 15 normal male, 15 normal female, and 19 iron-deficient subjects were 5.4$\pm$0.98, 4.6$\pm$0/76, and 18.0$\pm$12.8mg/1, respectively, and the difference in mean values between normal and iron deficient subjects was significant(p=0.0005). There existed the inverse logarithmic relationship(r=-0.9336, p<0.0001) between the serum TfR and ferritin levels.

• The Korean Journal of Nuclear Medicine
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• v.21 no.2
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• pp.143-150
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• 1987

To assess the analytic performance of immunoradiometric TSH assay (IRMA TSH), assay precision determined by intra and interassay variance, assay accuracy determined by dilution and recovery study, were evaluated by using two commercial kit $(Abott^{(R)}\;and\;Daichi^{(R)})$. Normal range of basal serum TSH and TRH stimulated TSH increment were also determined in 234 healthy subjects (male 110, female 124; age 20-70) and 30 voluteers (male 10, female 20; age 21-26). In addition, basal TSH levels of 70 patients with untreated hyperthyroidism, 50 untreated hypothyroidism, and 60 euthyroidism were measured to assess the clinical utility of IRMA TSH. The detection limit of IRMA TSH was 0.04 mU/l and 0.08 mU/l by Abott Kit and Daichi kit respectively. Using Abott kit, intra assay variance were 2.0, 3.1 and 1.4% in mean TSH concentration 2.4, 31.6 and 98.2 mU/l repectively and interassay variance were 2.0 and 3.2% in mean TSH concentration 2.3 and 31.3 mU/l. Mean recovery rate was 92.5% and dilution study showed nearly straight line. When Daichi kit was used, intrasssay variance were 5.6, 5.2 and 6.2% in mean TSH concentration of 2.4, 31.6 and 98.2 mU/l respectively and interassay variance were 7.1 and 7.4% in mean TSH of 2.3 and 31.3 mU/l. Mean recoveray rate was 89.9%. Normal range of basal TSH and TRH stimulated peak TSH were 0.38-4.02 mU/l and 2.85-30.8 mU/l repectively (95% confidence interval, Abott kit used). Sensitivity and specificity of basal TSH levels for diagnosing hypothyroidism as well as specificity for diagnosing hyperthyroidism were 100% by using both kit. Sensitivity of basal TSH level for diagnosing hyperthyroidism was 100% when TSH levels were measured by Abott kit while that was 80.9% when measured by Daichi kit. These results suggest that IRMA TSH was very precise and accurate method and might be used as a first line test in the evaluation of thyroid function.

• 대한핵의학회:학술대회논문집
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• 1987.05a
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• pp.112.2-113
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• 1987

• The Korean Journal of Nuclear Medicine Technology
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• v.27 no.1
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• pp.29-35
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• 2023

Purpose The concentration of PSA (Prostate Specific Antigen) after radical prostatectomy in prostate cancer patients is a predictor of biochemical recurrence, and the AUA (American Urological Association) is defined as biochemical recurrence when the concentration of PSA is measured at 0.2 ng/mL or more, and when the concentration is measured at 0.2 ng/mL or more at the retest. This standard is also applied our hospital. In this laboratory, the PSA reagent using IRMA (Immunoradiometric Assay) is used, and the sensitivity at a very low value was not as good as the reagent used in the department of laboratory medicine. This study aims to increase the reliability of the results by improving the precision and sensitivity of very low values. Materials and Methods As a reagent for the study, PSA reagent using IRMA was used. As a method to improve the precision and sensitivity of very low values, a variation method on the serum volume(25 uL, 50 uL, 100 uL, 200 uL) was studied, and variation usefulness evaluation was conducted. The evaluation items were compared the results of precision, analytical sensitivity, recovery rate, dilution test, high-dose hook effect test, parallel test and very low concentration values(n = 20). Results The validation results were displayed in the order of 25 uL, 50 uL, 100 uL, 200 uL. As the serum volume increased, it was confirmed that CV (Coefficient of Variation)(%) improved. Analytical sensitivity(ng/mL) was 0.038, 0.041, 0.017, 0.015 and recovery rate(%) was 101±3, 101±3, 99±2, 97±4. very low concentration values(ng/mL) between each volume(n=20) were 0.135±0.068, 0.076±0.050, 0.048±0.034, 0.046±0.034. and high dose hook effect appeared as the serum volume increased. Conclusion Through the variation usefulness evaluation, it was confirmed that as the serum volume increased, the precision and sensitivity improved at very low concentration values. However, it is necessary to pay special attention to the occurrence of high-dose hook effect as the serum volume increases. In the case of tests that requires very low concentration values, it is thought that the reliability of the result will be increased if the variation method is properly used after the variation usefulness evaluation.

• The Korean Journal of Nuclear Medicine
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• v.34 no.4
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• pp.353-359
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• 2000

Purpose: Although ${\alpha}$-fetoprotein is one of the most commonly used tumor markers in Korea, most of the radioimmunoassay kits for ${\alpha}$-fetoprotein have been imported from foreign countries. The purpose of this study was to evaluate the performance of a recently developed domestic immunoradiometric kit for ${\alpha}$-fetoprotein (Riakey AFP IRMA $CT^R$, Sin-Jin Medics, Seoul, Korea). Materials and Methods: We evaluated intra- and inter-assay precision, recovery rate, parallelism, and sensitivity of serum ${\alpha}$-fetoprotein measurement using Riakey AFP IRMA $CT^R$ kit. The values of ${\alpha}$-fetoprotein measured by Riakey AFP IRMA $CT^R$ kit were compared with those measured by two foreign commercial kits (${\alpha}$-fetoproteina of Radim and ${\alpha}$-feto.riabead of Abbott). Results: Intra-assay coefficients of variation on three different levels were 5.3% for 18.9 ng/ml, 3.4% for 133 ng/ml and 1.6% for 330 ng/ml. Inter-assay coefficients of variation were 9.7% for 20.9 ng/ml, 3.2% for 137 ng/ml and 4.1% for 330 ng/ml respectively. Recovery rate tests on all three different levels showed within $100{\pm}10%$. Parallelism was also good and the sensitivity was 0.63 ng/ml. There was strong correlation between the measurement of ${\alpha}$-fetoprotein by Riakey AFP IRMA $CT^R$ and that by two foreign commercial kits(r=0.98). Conclusion: The first Korean domestic immunoradiometric kit for ${\alpha}$-fetoprotein, Riakey AFP IRMA $CT^R$, performed well for clinical use.

• The Korean Journal of Pain
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• v.11 no.1
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• pp.150-154
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• 1998

Epidural steroid injection have become one of the most frequently applied conservative option for the management of acute and chronic back pain. As the indications for epidural steroid injections increase so do the adverse responses associated with this procedure. This study reports the succession of 3 patients who developed galactorrhea and hyperprolactinemia after recieving an epidural steroid injection for lumbar radiculopathy and low back pain. Serum prolactin level was elevated in accordance with epidural injection of corticosteroid. We measured the serum prolactin level by immunoradiometric assay method and peak serum prolactin level at above 500, 144.2, 150.3 ng/ml respectively. Also we found the serum prolactin level decreased to normal values 3 wks after corticosteroid injection. Galactorrhra ceased in advance of decrease of serum prolactin level. That "Hyperprolactinemia and galactorrhea can occur following epidural steroid injection", requires a much larger prospective investigation.

• The Korean Journal of Nuclear Medicine
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• v.38 no.6
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• pp.532-539
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• 2004

Purpose: There has been a renewal of interest in Macrophage migration inhibitory factor (MIF), especially correlation in pathogenesis of sepsis by many infectious diseases and in regulation of host inflammatory and immune response. We developed immunoradiometric assay (IRMA) to determine serum human MIF concentration. Materials and Methods: The IRMA system utilizes solid phase bound monoclonal anti-recombinant human MIF (rhMIF) antibody as a capture antibody, biotinylated polyclonal anti-rhMIF antibody as a detector antibody. We applied with rhMIF that concentration of standard solutions increased from 0 ng/ml to 100 ng/ml. We used $^{125}I$-streptavidin (SA) as radiotracer to determination of rhMIF concentration. Streptavidin was labeled with $^{125}I$ by Chloramine-T method and $^{125}I$-SA was purified by ultracentrifugation. $^{125}I$-SA stability was evaluated by ITLC analysis at $4^{\circ}C$ and room temperatures until 60days. To validate IRMA system for MIF, we experimented intra-assay and inter-assay coefficients of variation, recovery test and dilution test. Results: Radiolabeling yield of $^{125}I$-SA was 87% and purified $^{125}I$-SA retained above 99% radiochemical purity. $^{125}I$-SA showed above 93% stability in $4^{\circ}C$ until 60days that it is good for immunoradiometric assay as radiotracer. Plotted standard dose response curve showed that increased concentration of rhMIF linearly correlated (R2=0.99) with bound radioactivity of $^{125}I$-SA. The highest intra- and inter-assay coefficients of variation were 5.5% and 7.6%, respectively. The average of recovery of MIF in samples was 102%. In dilution test, linear response curves were obtained (R2=0.97). Conclusion: Radioimmunoassay using $^{125}I$-SA as radiotracer thought to be useful for the determination of serum MIF concentration, and further, its data will be used to evaluate the correlation between clinical significance and serum MIF concentration in patients with various inflammatory diseases.

• The Korean Journal of Nuclear Medicine
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• v.39 no.4
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• pp.252-256
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• 2005

Purpose: Thyroglobulin (Tg) is a valuable and sensitive tool as a marker for diagnosis and follow-up for several thyroid disorders, especially, in the follow-up of patients with differentiated thyroid cancer (DTC). Often, clinical decisions rely entirely on the serum Tg concentration. But the Tg assay is one of the most challenging laboratory measurements to perform accurately owing to antithyroglobulin antibody (Anti-Tg). In this study, we have compared the degree of Anti-Tg effects on the measurement of Tg between availale Tg measuring kits. Materials and Methods: Measurement of Tg levels for standard Tg solution was performed with two different kits commercially available (A/B kits) using immunoradiometric assay technique either with absence or presence of three different concentrations of Anti-Tg. Measurement of Tg for patient's serum was also performed with the same kits. Patient's serum samples were prepared with mixtures of a serum containing high Tg levels and a serum containg high Anti-Tg concentrations. Results: In the measurements of standard Tg solution, presence of Anti-Tg resulted in falsely lower Tg level by both A and B kits. Degree of Tg underestimation by h kit was more prominent than B kit. The degree of underestimation by B kit was trivial therefore clinically insignificant, but statistically significant. Addition of Anti-Tg to patient serum resulted in falsely lower Tg levels with only A kit. Conclusion: Tg level could be underestimated in the presence of anti-Tg. Anti-Tg effect on Tg measurement was variable according to assay kit used. Therefore, accuracy test must be performed for individual Tg-assay kit.

• Clinical and Experimental Reproductive Medicine
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• v.17 no.2
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• pp.101-106
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• 1990

Serum CA 125 was measured with immunoradiometric assay in fourty-one patients of endometriosis Serum CA 125 levels (Mean ${\pm}$ SEM, U/ml)in patients with endometriosis were 13.8${\pm}$3.3 in stage I , 17.3${\pm}$3.0 in stage II, 23.4${\pm}$4.9 in stage III, and 64.5${\pm}$13.2 in stage IV, which showed increment according to the stage of endometriosis. Serum levels in stage IV only were significantly elvated than those in control (15.3${\pm}$2.2), and those in advanced stage(III and IV ; 47.1${\pm}$9.5)were significantly higher than those in earlier stages (15.9${\pm}$2.2)and control. The assay revealed a sensitivity of 31.7% and the frequency of elevated levels (> 30.3 U/ml)in stage I, II, III and IV was 9. 1%, 18.8%,33.3%, and 87.5% respectively. Sensitivity in advanced stage was higher than that in earlier stage (64.3% vs. 14.8%). There data suggest that serum CA 125 assay might be a useful diagnostic tool in the advanced stage of endometriosis.