Rapid one-step modified technique in the evaluation of thyroglobulin by the immunoradiometric assay (IRMA) for monitoring differentiated thyroid carcinoma patients.

Objective: The aim of this study was to develop a modified one-step technique for measuring serum thyroglobulin (Tg), which is currently used as a tumor marker for differentiated thyroid carcinoma (DTC) by using the immunoradiometric assay (IRMA) of the THYROGLOBULINE IRMA kit as compared with the standard method. Methods: The surplus serum specimens from 111 DTC patients who had been treated and followed up at the Division of Nuclear Medicine, Department of Radiology and 105 healthy donors at the Department of Transfusion Medicine, Faculty of Medicine, Siriraj Hospital were included. The technique for serum Tg measurement was optimized from the two-step IRMA standard kits to the one-step modified method. Results: The one-step modified technique results in a decrease of turnaround time (TAT) from two days of both one-step and two-step gold standard kits to only two hours. The optimal volume of 125I - TgAb was found to be the same that of the kit’s technique. The optimal time for incubation was decreased from overnight at 17-18°C in the standard method to 90 minutes in a shaking water bath at 37°C. The analytical and functional sensitivities of the modified technique were 0.28 and 1.0 ng/ml, respectively. The coefficients of variation (%CV) of both intra-assay and inter-assay precision were 0.87-4.80% and 2.87-9.75%, respectively. The accuracies of the recovery test and dilution test were 92.74-101.82% and 101.27-109.16%, respectively. No cross-reaction presented between the anti-thyroglobulin antibodies and thyroid analogue compounds. The assays working range of Tg concentration under 10% CV of precision profile was 1.59-500 ng/ml. The correlation coefficient (r) between the results of the modified technique and the two-step standard method were excellent: r = 0.99; y = 1.349x-2.421; P < 0.001; n = 111. The reference range of Tg concentration among the euthyroid healthy subjects was 0.37-20.32 ng/ml (5th -95th percentile). Conclusion: The modified technique is simple, rapid, sensitive and reliable for monitoring the serum Tg level in DTC patients not only under stimulation but also during suppression therapy.

A method in field measurement of urinary iodine.

The objective of this study is to determine a very cheap, reliable, relatively rapid portable field unit for quantitative urinary iodine measurements. As Individual Urine Excretion (IUE) approximate those of Daily Iodine Intake (DII), iodine deficiency can be measured in casual urine samples of individual. Using the criteria, the frying pot method has been introduced and modified from the long and tedious Zak’s method after Pino et al, and Robbins and Dunn et al. This modified method has many advantages. Such the assay takes 84 tubes of urine per pot in100o C paraffin oil bath and changes into water. It has been shortened from one hour to 25 minutes. Change of color to intermediate violet is observed by adding ferroine as the indicator, resulting in a standard curve reading the concentration of iodine being, in micrograms per liter. The results of 255 subjects from Mukdaharn Province indicated the reliability of the method as the results of which are the same as those using in the heating block and spectrophotometespectrophotomete. This has been confirmed by the results of 1,007 samples. This new technique provides good results; between oil and water, the results on using water are even better. This saves much money modification reduces significantly by lowering the cost of equipment. It is rapid, simple and reliable. The method is portable and valuable for measuring and monitoring iodine deficiency studies and for epidemiological studies of iodine deficiency its control in developing countries.

Urine iodine inresligalion in Thailand.

The heating block method is a method for the routine determination of urine iodine that has been modified from the Program Against Micronutrient Malnutrition (PAMM) method. Normal values of adult urine iodine (age 35-70 years) in Bangkok were (mean + SD) 110.9+ 74.6 with a median values of 96.8 ตg/L (n = 66). Urine iodine values of adults from Maehongson and Petchabun were (mean + SD) 465.1+ 293.1 with a median value of 399.5 ตg/L (n=86), and 127.8+ 74.1 with a median value of 115.4 mg/L (n = 140), respectively. The mean and SD of the iodine content of urine from school children (age 7-12 years) in Uttraradit, Maehongson and Trang were 401.0+ 373.2 (n = 77), 1,171.1+ 1,078.4 (n = 97) and 275.0+ 399.4 (n = 46), and the median values were 264.5, 998.6 and 137.0 mg/L, respectively. There was no change in urine iodine concentration over three years despite storage a 37oC, 4 oC and 0 oC. We have participated in the PAMM-Centers for Disease Control and Prevention (CDC) Inter-Laboratory Urine Iodine Quality Assurance Program to fulfill quality assurance criteria in our testing. The results of three blind urine iodine levels were well correlated to consensus mean and %CV for inter assays were less than 15.

An investigation into methods of urine iodine analysis for use among villagers with goitre.

A modified Zak’s method has been used in this laboratory, but was subjected to contamination and produced occasional inconsistent results. Two simple ways for the determination of iodine in urine are herein described. The better one is by modified PAMM method. Briefly, destruction of organic matter in urine by acid digestion is carried out prior to determination by the Sandell and Kolthoff reaction. The Coefficient of Variation (CV) is below 10%. Iodine contents as low as 6.5 ug/L, can be detected. The proposed acid digestion procedure offers some advantages over the traditional acid digestion : e.g. low iodine losses, not complicated, and less harsh digestion. The method does not require large samples (250 ul or below) and one technician can easily handle 100 samples per day. The results obtained by this method are well correlated between the simple methods and agree with those recorded by other workers. This is also in agreement with Zak’s method (Intraclass Correlation Coefficient of 0.55). The proposed method is rapid, simple, cheap and suitable for the research investigations on iodine deficiency goitre in areas where it is endemic.

Iodine deficiency disorders: Recent experience with iodine technology in Thailand.

For the control Iodine Deficiency Disorders (IDD) in Thailand, simple methods for iodination of various food supplements have been introduced by making use of: a) a single bottle of concentrated KIO3 solution which can be prepared by village health volunteers. Iodine may be administered by consumers by dripping the concentrate into drinking water containers belonging to village households, water for school lunch programmes, by spray mixing with salt or by dripping into fish sauce. b) twin bottle for instant detection of iodine in salt and water. This instant test is very useful for on site monitoring and hence surveillance. On a mass scale, iodination of common salt was undertaken by a simple but high capacity spraying machine or by manual mixing on a spraying table. At village level, salt iodination can be undertaken by hand spraying in a plastic basin. Iodination of drinking water can be facilitated either by using a single dropper bottle of conc KIO3 solution, or iodinators. On a limited scale, oral lipiodol has been utilized with success and the synthesis of iodized oil has been attempted. Supporting evidence from field trials confirmed the effectiveness of present methods of control via the iodated salt programme, (1962-1968), iodinated water in village households and school lunch programmes (1986-1988), iodinated water by iodinators (1981-1988), oral iodized oil (1987-1989), and iodinated water and iodated salt (1988-1989). Education transfer, and pitfalls found in the control and evaluation programmes were carefully followed up. Future projections of the control programme have been discussed.