Quantification of Organophosphorus Insecticide Removed by Gastric Lavage in Acutely Poisoned Patients: An Observational Study.

Introduction: The effectiveness of gastric lavage in organophosphorus (OP) poisoning has not been established. We assessed the ability of gastric lavage to remove OP insecticides as a preliminary stage in assessing effectiveness. Patients and methods: Organophosphorus poisoning patients presenting within 6 hours were included, irrespective of prior gastric lavage. A nasogastric tube was placed and gastric contents aspirated, followed by at least three cycles of gastric lavage with 200 mL of water. Samples from the initial aspirate and the first three lavage cycles were sent for identification and quantification of the OP compounds. Patients were monitored for complications of gastric lavage. Results: Around 42 patients underwent gastric lavage. Eight (19.0%) patients were excluded from the study because of a lack of analytical standards for ingested compounds. Insecticides were detectable in the lavage samples of 24 of 34 (70.6%) patients. Lipophilic OP compounds were detected in 23 of 24 patients, while no hydrophilic OP compounds could be detected in six patients with reported ingestion of hydrophilic compounds. For chlorpyrifos poisoning (n = 10), only 0.65 mg (SD 1.2) of the estimated ingested amount (n = 5) of 8,600 mg (SD 3,200) was recovered by gastric lavage. The mean proportion of the compound removed by initial gastric aspirate was 79.4% and subsequent three cycles removed 11.5, 6.6, and 2.7%. Conclusion: Lipophilic OP insecticides could be quantified in the stomach contents of OP poisoning patients with the first aspiration or lavage being most effective. The amount removed was very low; hence, routine use of gastric lavage for OP poisoning patients arriving within 6 hours is unlikely to be beneficial. How to cite this article: Mathansingh AJ, Jose A, Fleming JJ, Abhilash KPP, Chandiraseharan VK, Lenin A, et al. Quantification of Organophosphorus Insecticide Removed by Gastric Lavage in Acutely Poisoned Patients: An Observational Study. Indian J Crit Care Med 2023;27(6):397-402.

Role of hyperhomocysteinemia and Vitamin B12 deficiency in central and hemi-central retinal vein occlusion: A case-control study.

BACKGROUND: Retinal venous occlusive diseases have been recognized as a major cause of ocular morbidity. Hyperhomocysteinemia could be a potentially modifiable risk factor. OBJECTIVE: To determine the association of hyperhomocysteinemia with central and hemi-central retinal vein occlusion (CRVO and HCRVO), the correlation of serum levels of homocysteine with Vitamin B12 and folate levels and the association of Vitamin B12 deficiency with hyperhomocysteinemia. METHODS: In this case-control study, patients with CRVO and HCRVO, and age- and gender-matched controls without CRVO and HCRVO, who met the eligibility criteria, were enrolled after obtaining informed consent. Data obtained from participants using a questionnaire, complete ophthalmological examination and relevant investigations, including estimation of serum homocysteine, Vitamin B12 and folate levels, were collated and analyzed. RESULTS: Thirty-nine cases with CRVO and HCRVO and 39 age- and gender-matched controls were studied. We found a significant association of hypertension (P < 0.01), hyperlipidemia (P = 0.01), and abnormal blood profile (P < 0.01) with retinal vein occlusion. There was no statistically significant association of hyperhomocysteinemia with CRVO and HCRVO (P = 0.81). However, we found a high prevalence of both hyperhomocysteinemia (43.58% of cases and 53.84% of controls; P = 0.81) and Vitamin B12 deficiency (23.08% of cases and 38.46% of controls; P = 0.14) in cases and controls, without a statistically significant difference between the two groups with respect to both parameters. Our study also found a negative correlation of serum levels of homocysteine with Vitamin B12 (Pearson correlation co-efficient - 0.3874, P = 0.0005), and folate (Pearson correlation coefficient - 0.3886, P = 0.0004) of the study participants. Among the study participants (n = 78), the odds of patients with Vitamin B12 deficiency having hyperhomocysteinemia were 7.0 (2.26-21.72) times those of patients without Vitamin B12 deficiency (P = 0.001). Similarly, among the cases (CRVO, n = 39), the odds of patients with Vitamin B12 deficiency having hyperhomocysteinemia were 7.0 (1.22-40.09) times those of patients without Vitamin B12 deficiency (P = 0.029). In the control group also (non-CRVO, n = 39), the odds of patients with Vitamin B12 deficiency having hyperhomocysteinemia were 6.67 (1.47-30.21) times those of patients without Vitamin B12 deficiency (P = 0.014). CONCLUSION: Hyperhomocysteinemia was not found to be an independent risk factor for retinal vein occlusion in our study. However, we found a high prevalence of hyperhomocysteinemia and Vitamin B12 deficiency in both cases and controls, without a statistically significant difference between the two groups with respect to both parameters. We also found a negative correlation of serum homocysteine levels with Vitamin B12 and folate levels. The odds of patients with Vitamin B12 deficiency having hyperhomocysteinemia were seven times those of patients without Vitamin B12 deficiency. Hypertension, hyperlipidemia, and abnormal blood profile had a significant association with CRVO and HCRVO. Many of the systemic risk factors for retinal vein occlusions are found to be associated with elevation of serum homocysteine levels, which may be part of a final common pathway in bringing about a state of accelerated atherosclerosis, leading to CRVO or HCRVO. Therefore, lowering serum levels of homocysteine by Vitamin B12 and folate supplementation could have a role in the prevention of these diseases.

Clinical presentation of type 1 and type 2 pyrethroid poisoning in humans.

BACKGROUND: It is unclear if the clinical presentation of poisoning with type 1 and type 2 pyrethroid compounds is different. This study was undertaken to detail the clinical profile and outcome of patients presenting with pyrethroid poisoning and to quantify serum pyrethroid levels. PATIENTS AND METHODS: In this prospective study, patients were categorised as poisoning with type 1 pyrethroids or type 2 pyrethroids. Blood samples were sent for compound identification and quantification. Clinical features and outcomes were compared between the two groups. Factors associated with moderate and severe toxicity were explored using univariate logistic regression analysis and presented as odds ratio (OR) and 95% confidence intervals (CI). RESULTS: Type 1 pyrethroids were implicated in 16 patients and type 2 in 43 patients. The incidence of nausea and vomiting (81.2% vs. 81.3%) and tremor (37.5% vs. 32.6%) were similar in type 1 and type 2 poisoning; paraesthesia (6.2% vs. 32.6%, p = 0.04), hypersalivation (0% vs. 20.9%, p = 0.04), seizures (0% vs. 7%, p = 0.29) and depressed sensorium (0% vs. 18.6%, p = 0.03.) were observed more frequently in type 2 pyrethroid poisoning. Pyrethroids were detected in the serum samples of 24 patients; quantification was possible in 22 patients in whom serum levels ranged from 1.1 to 453 µg/ml. The compounds were undetectable in 35 patients. Two patients (lambda-cyhalothrin poisoning and cypermethrin poisoning) required intubation for low sensorium and respiratory distress. The median (interquartile range) duration of hospitalization was 12 (12-24) hours. All patients survived. Factors associated with moderate and severe toxicity included ingestion of a type 2 pyrethroid, lambda-cyhalothrin (OR 7.81, 95%CI 1.55-39.37, p = 0.01) and volume ingested (OR 1.01, 95%CI 1.00-1.02, p = 0.02). CONCLUSION: Patients with pyrethroid poisoning present predominantly with mild to moderate symptoms. Paraesthesia and hypersalivation are more frequent in type 2 poisoning. A favourable outcome can be expected.

Effects of Fluoride on Bone in an Animal Model of Vitamin D Deficiency.

We investigated the combined effect of fluoride exposure and Vitamin D deficiency in causing bone damage as a precursor to development of Fluorotoxic Metabolic Bone Disease. Thirty-six male Sprague-Dawley rats were divided into 6 groups of six; 3 groups received a Vitamin D deficient diet whereas the other 3 received a Vitamin D adequate diet. Serum total 25-hydroxyvitamin D (25OHD), calcium, phosphorus, creatinine, Alkaline phosphatase (ALP), albumin, Parathyroid hormone (PTH), Osteocalcin and C terminal telopeptide (CTx) were measured following exposure to varying levels of fluoride in drinking water (< 1.0, 15 and 50 ppm). Full body Dual-energy X-ray Absorptiometry (DXA) scans were used to examine changes in bone morphology pre and post exposure to fluoride. Renal tubular function was assessed using serum creatinine and urine Cystatin C. Histopathological examination of sections of bone and kidney tissues were also performed. Prior to fluoride exposure, DXA scans revealed a significant decrease in Bone Mineral Density (BMD) and Bone Mineral content (BMC) (p < 0.05) but a significant increase in fat mass (p < 0.05) and fat percentage (p < 0.01) among Vitamin D deficient rats, with no significant change in biochemical parameters. Following exposure to fluoride, BMD was significantly increased (p < 0.05) in both groups with a corresponding increase in serum ALP, bone fluoride content, Osteocalcin, CTx and urine fluoride with increasing levels of fluoride exposure. Serum creatinine calcium and phosphate and urinary cystatin C levels showed no significant changes. Light microscopy examination revealed mild thickening and increased osteoid in 80% of the Vitamin D deficient rats exposed to high levels of fluoride but renal tubular changes were found only in one experimental and one control animal. Fluoride deposited in rat bone affects both osteoblastic and osteoclastic activity. Also, these effects are accentuated in the presence of Vitamin D deficiency.

Validating a High Performance Liquid Chromatography-Ion Chromatography (HPLC-IC) Method with Conductivity Detection After Chemical Suppression for Water Fluoride Estimation.

A variety of methods, including the Ion Selective Electrode (ISE), have been used for estimation of fluoride levels in drinking water. But as these methods suffer many drawbacks, the newer method of IC has replaced many of these methods. The study aimed at (1) validating IC for estimation of fluoride levels in drinking water and (2) to assess drinking water fluoride levels of villages in and around Vellore district using IC. Forty nine paired drinking water samples were measured using ISE and IC method (Metrohm). Water samples from 165 randomly selected villages in and around Vellore district were collected for fluoride estimation over 1 year. Standardization of IC method showed good within run precision, linearity and coefficient of variance with correlation coefficient R2 = 0.998. The limit of detection was 0.027 ppm and limit of quantification was 0.083 ppm. Among 165 villages, 46.1% of the villages recorded water fluoride levels >1.00 ppm from which 19.4% had levels ranging from 1 to 1.5 ppm, 10.9% had recorded levels 1.5-2 ppm and about 12.7% had levels of 2.0-3.0 ppm. Three percent of villages had more than 3.0 ppm fluoride in the water tested. Most (44.42%) of these villages belonged to Jolarpet taluk with moderate to high (0.86-3.56 ppm) water fluoride levels. Ion Chromatography method has been validated and is therefore a reliable method in assessment of fluoride levels in the drinking water. While the residents of Jolarpet taluk (Vellore distict) are found to be at a high risk of developing dental and skeletal fluorosis.

Expression of metallothionein in dimethylhydrazine-induced colonic precancerous and cancerous model in rat.

AIM: Metallothionein (MT) is a small protein with a high affinity for divalent heavy metals and has a function in zinc homeostasis. The purpose of this study was to assess the MT mRNA gene expression as well as the MT protein content by immunohistochemistry and radioimmunoassay (RIA) in 1,2-dimethylhydrazine (DMH)-induced precancerous and cancerous colonic tissue in rats. MATERIALS AND METHODS: Six-week-old rats were given subcutaneous injections of DMH twice a week for 3 months and sacrificed at 4 months (precancerous model) and 6 months (cancerous model). We determined MT mRNA expression by reverse transcription polymerase chain reaction and MT protein content by both immunohistochemical expression and cadmium-109 RIA. RESULTS: MT mRNA expression in the large intestine showed statistically significant decrease in the precancerous (P < 0.01) and the cancerous (P < 0.001) model as compared with controls. Immunohistochemical expression of MT showed statistically significant decrease (P < 0.05) in the colonic cancerous tissue. MT content in the large intestine showed statistically significant decrease in precancerous (P < 0.005) and cancerous (P < 0.001) model as compared with controls. CONCLUSION: This study suggests that a decrease in the colonic MT mRNA expression, MT protein expression, and content in DMH-induced colonic cancer model is associated with the development of preneoplastic lesions and further progression to carcinoma in the colon results in a greater reduction in the levels of each of these parameters.

Estimation of Monocrotophos renal elimination half-life in humans.

INTRODUCTION: Monocrotophos, implicated in about 1/4th of organophosphate poisonings in our centre, is associated with the highest mortality (24%). Yet data on its pharmacokinetics in humans is limited. We estimated the renal elimination half-life of monocrotophos. PATIENTS AND METHODS: Consecutive patients presenting with monocrotophos overdose over a 2-month period who had normal renal function were recruited. Monocrotophos in plasma and urine were quantitated by high-performance liquid chromatography. Urine was obtained from catheterised samples at 0-2, 2-4, 4-6, 6-8, 8-12 and 12-24 h. Plasma specimens were collected at the time of admission, and at the midpoint of the urine sample collections at 1, 3, 5, 7, 10, 15 and 21 h. Renal elimination half-life was calculated from the cumulative amount excreted in the urine. RESULTS: The cohort of 5 male patients, aged 35.8 ± 2.94 years, presented with typical organophosphate (cholinergic) toxidrome following intentional monocrotophos overdose. All patients required mechanical ventilation; one patient died. Plasma data was available from 5 patients and urine data from 3 patients. The median renal elimination half-life was 3.3 (range: 1.9-5.0 h). Plasma monocrotophos values, as natural log, fell in a linear fashion up to around 10 h after admission. After the 10-hour period, there was a secondary rise in values in all the 3 patients in whom sampling was continued after 10 h. CONCLUSION: A renal elimination half-life of 3.3 h for monocrotophos is consistent with a water-soluble compound which is rapidly cleared from the plasma. The secondary rise in plasma monocrotophos values suggests possible re-distribution. Determining the elimination profile of this compound will help develop better strategies for treatment.

Protective role of aspirin, vitamin C, and zinc and their effects on zinc status in the DMH-induced colon carcinoma model.

Chemoprotection refers to the use of specific natural or synthetic chemical agents to suppress or prevent the progression to cancer. The purpose of this study is to assess the protective effect of aspirin, vitamin C or zinc in a dimethyl hydrazine (DMH) colon carcinoma model in rats and to investigate the effect of these supplements on changes associated with colonic zinc status. Rats were randomly divided into three groups, group 1 (aspirin), group 2 (vitamin C) and group 3 (zinc), each being subdivided into two groups and given subcutaneous injection of DMH (30 mg/kg body wt) twice a week for 3 months and sacrificed at 4 months (A-precancer model) and 6 months (B-cancer model). Groups 1, 2, 3 were simultaneously given aspirin, vitamin C, or zinc supplement respectively from the beginning till the end of the study. It was observed that 87.5% of rats co-treated with aspirin or vitamin C showed normal colonic histology, along with a significant decrease in colonic tissue zinc at both time points. Rats co-treated with zinc showed 100% reduction in tumor incidence with no significant change in colonic tissue zinc. Plasma zinc, colonic CuZnSOD (copper-zinc superoxide dismutase) and alkaline phosphatase activity showed no significant changes in all 3 cotreated groups. These results suggest that aspirin, vitamin C or zinc given separately, exert a chemoprotective effect against chemically induced DMH colonic preneoplastic progression and colonic carcinogenesis in rats. The inhibitory effects are associated with maintaining the colonic tissue zinc levels and zinc enzymes at near normal without significant changes.

Zinc and zinc related enzymes in precancerous and cancerous tissue in the colon of dimethyl hydrazine treated rats.

Trace element zinc deficiency or excess is implicated in the development or progression of some cancers. The exact role of zinc in the etiology of colon cancer is unclear. To cast light on this question, an experimental model of colon carcinogenesis was applied here. Six week old rats were given sub cutaneous injections of DMH (30 mg/kg body weight) twice a week for three months and sacrificed after 4 months (precancer model) and 6 months (cancer model). Plasma zinc levels showed a significant decrease (p<0.05) at 4 months and a greater significant decrease at 6 months (p<0.01) as compared with controls. In the large intestine there was a significant decrease in tissue zinc levels (p<0.005) and in CuZnSOD, and alkaline phosphatase activity (p<0.05) in the pre-cancerous model and a greater significant decrease in tissue zinc (p<0.0001), and in CuZnSOD and alkaline phosphatase activity (p<0.001), in the carcinoma model. The tissue zinc levels showed a significant decrease in the small intestine and stomach (p<0.005) and in liver (p<0.05) in the cancer model. 87% of the rats in the precancer group and 92% rats in the cancer group showed histological evidence of precancerous lesions and carcinomas respectively in the colon mucosa. This study suggests that the decrease in plasma zinc, tissue zinc and activity of zinc related enzymes are associated with the development of preneoplastic lesions and these biochemical parameters further decrease with progression to carcinoma in the colon.

Anomalous Activity Measurements of Creatine (Phospho) Kinase, CK-MB Isoenzyme in Indian Patients in the Diagnosis of Acute Coronary Syndrome.

In the present study, the cause of suspected false-positive (anomalous) values for CK-MB activity, in Indian patients investigated for ACS. Total serum CK and CK-MB activity, serum Troponin I were measured and CK-MB as a percentage of the total CK activity (%CK-MB) calculated. CK-MB was also estimated using densitometry and CK-MB mass assay. Anomalous specimens were tested for the presence of CK isoenzymes. In 22 healthy subjects, 11 male and female, the %CK-MB ranged from 3.6 to 30.2. In 11 male patients, with proven ACS, the %CK-MB was from 4.0 to 17.5. The cut off for anomalous CK-MB activity values was set as >33.0%. In 35 patients with anomalies, total CK values ranged from 39 to 231 U/L, CK-MB from 30 to 161 U/L. Investigation of CK isoenzymes, showed 10 patients had a CK-BB band, 14 an intermediate band between CK-MM and CK-MB (macro-CK type 1), 7 had a cathodal band (macro-CK type 2), and 3 had a band intermediate between CK-MB and CK-BB. This later band does not seem to have been previously reported. Against the CK-MB mass assay, the activity assay showed no correlation, in 43 patients (19 M, 24 F), Pearson coefficient (R(2)) was 0.006. The CK-MB immunoinhibition assay is better described as measuring "non-CK-MM activity." A %CK-MB activity >6% as a marker of ACS is not valid in our patient population. Laboratories should not use only CK-MB activity as a biochemical marker of ACS.

Clinical profile and outcome of patients hospitalized with dimethyl and diethyl organophosphate poisoning.

UNLABELLED: The two major classes of organophosphate compounds, dimethyl and diethyl organophosphates, have different toxicokinetic properties. This study evaluated the clinical profile and outcomes in patients admitted with poisoning with these two classes of organophosphates. METHODS: This retrospective study spanned 6 years (2002-2007). Patients were treated with atropine and supportive care including ventilation, as required, and followed up until death or hospital discharge. Oximes were not administered. Of the 422 charts retrieved, 396 fulfilled inclusion criteria. Data on the clinical profile, ventilation, length of hospital stay, incidence of intermediate syndrome and mortality were extracted. RESULTS: The mean (± standard deviation) age was 31.4 ± 12.7 years with a male preponderance (2.6:1). The median (interquartile range (IQR)) admission pseudocholinesterase level of 317 (222-635) U/L indicated significant inhibition of cholinesterase activity. The median lag-time to presentation to our hospital was 5 (IQR 3-8.5) hours. Oximes were administered at a primary center in 33 patients (8.3%). Dimethyl organophosphate was ingested by 141 patients, diethyl organophosphate by 108, S-alkyl organophosphate by 2, and an un-identified organophosphate by 145 patients. Ventilation was required in 260 patients (65.7%); the median duration of ventilation being 7.5 (IQR 3-12) days. Overall mortality was 13.1%. There was a significant difference between dimethyl and diethyl organophosphate compounds in ventilatory requirement (76% vs. 56%, adjusted odds ratio (OR) 2.37, 95% CI 1.01-5.57, p=0.047), duration of ventilation (11 (4-15) vs. 5 (2-9) days, adjusted OR 1.12, 95%CI 1.04-1.21, p=0.002) and incidence of intermediate syndrome (72/125 (58%) vs. 24/92 (26%), adjusted OR 2.84, 95%CI 1.38-5.86, p=0.004). Mortality was similar in the two groups (20/141 (14%) vs. 7/108 (6%), dimethyl vs. diethyl organophosphate, adjusted OR 1.29, 95%CI 0.43-3.94, p=0.65). CONCLUSIONS: Patients admitted with dimethyl organophosphate poisoning have a worse outcome compared with diethyl organophosphate poisoning for clinically relevant patient outcomes.

Bioscavenger therapy for organophosphate poisoning - an open-labeled pilot randomized trial comparing fresh frozen plasma or albumin with saline in acute organophosphate poisoning in humans.

INTRODUCTION: Traditional treatment of organophosphate poisoning (OP) with oximes has had limited success. Fresh frozen plasma (FFP) or albumin, acting as bioscavengers to mop up free organophosphate, has been recently proposed as a treatment modality. In this pilot open-label, three-arm, randomized controlled study exploring proof of concept, we evaluated if bioscavenger therapy had a role in OP. PATIENTS AND METHODS: Sixty patients with significant poisoning presenting within 12 hours, with suppression of pseudocholinesterase activity to < 1,000 U/L, were randomized to receive FFP (8 bags, 250 mL each over 3 days), 20% human albumin (4 × 100 mL over 3 days), or saline (2,000 mL over 3 days) in addition to atropine and supportive care. Pseudocholinesterase and organophosphate levels were measured pretreatment, post-infusion (Day 2, Day 3), and predischarge and expressed as mean ± standard error. The incidence of intermediate syndrome, need for mechanical ventilation, atropine requirement, and mortality were assessed. RESULTS: Twenty patients received albumin and 19 patients each FFP or saline. FFP increased pseudocholinesterase levels (250 ± 44-1,241 ± 364 U/L) significantly (p = 0.007). Small, nonsignificant increases were observed with saline (160 ± 30-259 ± 78) and albumin (146 ± 18-220 ± 61). Organophosphate levels reduced in all 3 arms; no clear-cut trends were observed. We observed more cases of intermediate syndrome with FFP [10/19 (53%) vs. 5/20 (25%) vs. 5/19 (26%), FFP, albumin, and saline arms (p = 0.15)]. The interventions did not affect ventilatory requirements (14/19 vs. 15/20 vs. 14/19) or prevent delayed intubation. There were no differences in mean (±standard error) atropine requirement (in milligrams) in the first 3 days (536 ± 132 vs. 361 ± 125 vs. 789 ± 334) and duration (in days) of ventilation (10.0 ± 2.1 vs. 7.1 ± 1.5 vs. 7.5 ± 1.5) or hospital stay (12.4 ± 2.2 vs. 9.8 ± 1.4 vs. 9.8 ± 1.6). Two patients developed adverse effects with FFP. Mortality was similar (4/19 vs. 5/20 vs. 2/19, p = 0.6). CONCLUSIONS: Despite significant increase in pseudocholinesterase levels with FFP, this pilot study did not demonstrate favorable trends in clinical outcomes with FFP or albumin.

Tissue zinc levels in precancerous tissue in the gastrointestinal tract of azoxymethane (AOM)-treated rats.

Alterations in tissue zinc levels have been documented in patients with gastrointestinal tract malignancies and more frequently, in those with colonic cancer. However, the precise role of tissue zinc in carcinogenesis is not well elucidated. This study, using a well-established colon cancer model in rats, was designed to investigate the relationship of tissue zinc to the carcinogenic process. The aim was to examine tissue zinc levels in the preneoplastic tissues and to study the changes that occur during transition of mucosa from normal to preneoplastic state. Six-week old rats were given a single dose subcutaneous injection of azoxymethane (AOM) (30mg/kg body weight) and sacrificed after 1, 2, 5, and 9 months of the treatment. Plasma zinc levels showed a significant decrease (p<0.05) at 9 months compared with controls. Tissue zinc levels showed a significant decrease in the large intestine at 1 and 2 months (p<0.05) and at 5 and 9 months (p<0.01), in the small intestine at 2, 5, and 9 months (p<0.05), and in the stomach at 5 and 9 months (p<0.05). The maximum percent decrease (45%) in tissue zinc was observed in the large intestine at 9 months. Tissue copper zinc super oxide dismutase (CuZnSOD) activity was assessed in the body of the stomach, small intestine, and large intestine and compared with the control group. There was a significant fall in CuZnSOD levels in the small intestine at 9 months (p<0.05) and in the large intestine at 5 and 9 months (p<0.01). Two of these six rats showed histological evidence of precancerous lesions in the mucosa of the colon. This study suggests that the decrease in plasma zinc, tissue zinc and activity of CuZnSOD is associated with development of preneoplastic lesions in the colonic mucosa.

Measurement of renal function in kidney donors using serum cystatin C and beta(2)-microglobulin.

BACKGROUND: The usefulness of serum cystatin C and serum beta(2)-microglobulin (B2M) as markers of glomerular filtration rate (GFR) were compared in kidney donors before and after nephrectomy. METHODS: Blood samples were taken from 28 donors (15 women and 13 men) for serum creatinine, urea, cystatin C and B2M estimation a median of 7 days before and 10 days after nephrectomy. RESULTS: Estimated GFR decreased from a median of 86.2 mL/min/1.73 m(2) to 60.3 mL/min/1.73 m(2), a median decrease of 28.6%. Serum creatinine increased by 40% and urea by 30.4%; serum cystatin C increased by 31.2% and serum B2M increased by 65.6%. Using published data on biological variation, critical values were calculated. An increase in serum creatinine above 18 micro mol/L detected the decline in renal function in 26/28 (92.9%) subjects. Increases in serum B2M greater than a critical value of 0.94 mg/L detected 24/28 (85.7%) of these subjects, but the critical value of 0.59 mg/L for cystatin C detected only 8/28 (28.6%). CONCLUSION: Using critical values, serial measurement of serum creatinine was better than serum B2M in detecting reduced renal function. Because of its large intraindividual variation, serial serum cystatin C estimation was very poor in detecting reduced renal function.