New Model for Estimating Glomerular Filtration Rate in Patients With Cancer.

Purpose The glomerular filtration rate (GFR) is essential for carboplatin chemotherapy dosing; however, the best method to estimate GFR in patients with cancer is unknown. We identify the most accurate and least biased method. Methods We obtained data on age, sex, height, weight, serum creatinine concentrations, and results for GFR from chromium-51 (51Cr) EDTA excretion measurements (51Cr-EDTA GFR) from white patients ≥ 18 years of age with histologically confirmed cancer diagnoses at the Cambridge University Hospital NHS Trust, United Kingdom. We developed a new multivariable linear model for GFR using statistical regression analysis. 51Cr-EDTA GFR was compared with the estimated GFR (eGFR) from seven published models and our new model, using the statistics root-mean-squared-error (RMSE) and median residual and on an internal and external validation data set. We performed a comparison of carboplatin dosing accuracy on the basis of an absolute percentage error > 20%. Results Between August 2006 and January 2013, data from 2,471 patients were obtained. The new model improved the eGFR accuracy (RMSE, 15.00 mL/min; 95% CI, 14.12 to 16.00 mL/min) compared with all published models. Body surface area (BSA)-adjusted chronic kidney disease epidemiology (CKD-EPI) was the most accurate published model for eGFR (RMSE, 16.30 mL/min; 95% CI, 15.34 to 17.38 mL/min) for the internal validation set. Importantly, the new model reduced the fraction of patients with a carboplatin dose absolute percentage error > 20% to 14.17% in contrast to 18.62% for the BSA-adjusted CKD-EPI and 25.51% for the Cockcroft-Gault formula. The results were externally validated. Conclusion In a large data set from patients with cancer, BSA-adjusted CKD-EPI is the most accurate published model to predict GFR. The new model improves this estimation and may present a new standard of care.

Validation and impact of a new technique for assessment of glomerular filtration rate in patients with liver disease.

OBJECTIVES: Previously we have proposed a technique for the measurement of plasma clearance in patients with ascites. The impact of using the technique was assessed and the results compared with those from a reference technique in 111 patients having glomerular filtration rate measurements as part of their workup for liver transplantation. METHODS: Results of calculations using the new technique were compared with plasma clearance measurements obtained using a conventional slope-intercept technique and with clearance measurements based on urine collection. Discrepancies between the results of plasma clearance and urinary clearance assessments were investigated by using an uncollimated gamma camera to measure the total retention of the tracer. RESULTS: Conventional slope-intercept calculations overestimated clearance compared with the new technique by more than 20% in 21% of the patients. Significant differences between the results of the two methods were more likely in patients with more severe ascites. Results of urine collection-based measurements of Cr-51 EDTA clearance were frequently significantly lower than measurements using the new technique, whereas measurements of urinary clearance of creatinine were higher. Gamma camera measurements suggest that discrepancies between total and urinary clearance of Cr-51 EDTA are due to incomplete urine collection. CONCLUSION: The new technique is a practical method for assessment of kidney function and should be used in patients with liver disease who have or may have ascites.

Increased intestinal permeability to oral chromium (51 Cr) -EDTA in human Type 2 diabetes.

OBJECTIVE: In animal models of obesity and Type 2 diabetes, permeability of the intestine is increased because of impairment of tight junction proteins, allowing translocation of bacterial endotoxin and resulting in low-grade systemic inflammation. This has yet to be demonstrated in humans. The objective of this study was the demonstration of increased intestinal permeability in human Type 2 diabetes. METHODS: We examined intestinal permeability using chromium ((51) Cr)-EDTA urinary recovery in twenty well-controlled men with Type 2 diabetes compared with control subjects matched for age, gender and BMI. RESULTS: Intestinal permeability was significantly increased (P = 0.002) in the diabetic group and was correlated to increased levels of systemic inflammatory markers high-sensitivity C-reactive protein (r = 0.694, P = 0.001), interleukin 6 (r = 0.548, P = 0.012) and tumour necrosis factor alpha (r = 0.564, P = 0.010). CONCLUSION: This is the first demonstration that increased intestinal permeability may be a feature of human Type 2 diabetes.

Reliability of 5¹Cr-EDTA plasma and urinary clearance as a measure of residual renal function in dialysis patients.

PURPOSE: In dialysis patients, longer survival is associated with a higher residual renal function. Randomized controlled trials are conducted to clarify how residual renal function can be preserved. However, existing methods for measuring residual renal function are uncertain and there is a need for establishing a standard for measurements of glomerular filtration rate (GFR) in dialysis patients. METHODS: 5¹Cr-EDTA clearances in plasma, urine, and dialysate were evaluated in a sample of 12 hemodialysis and 12 peritoneal dialysis patients. The patients' condition was generally stable, and all patients were investigated twice within 4-10 days. RESULTS: Plasma clearances of 5¹Cr-EDTA for all patients ranged between 2.1 and 30.8 mL/min/1.73 m², whereas urinary 5¹Cr-EDTA clearances ranged from 0.7-20.0 mL/min/1.73 m². This difference was statistically significant (p < 0.001). Week-to-week reproducibility expressed as coefficients of variation were below or equal to 10% for plasma clearances and 13% for urinary clearances in hemodialysis patients and 14% in peritoneal dialysis patients. CONCLUSIONS: This study demonstrated a difference between 5¹Cr-EDTA plasma and urinary clearances in dialysis patients. Plasma clearance of 5¹Cr-EDTA had the best reproducibility. For repeated measurements as in clinical prospective trials, we recommend 5¹Cr-EDTA plasma clearance based on blood sampling at 5 + 24 hours with subtraction of 5¹Cr-EDTA dialysate clearance in peritoneal dialysis patients. Further studies are needed to corroborate our findings.

Application of the 51Cr-EDTA urinary recovery test for assessment of intestinal permeability in the horse.

Altered intestinal permeability is implicated in the pathogenesis of diverse equine medical conditions including alimentary laminitis and protein-losing enteropathies associated with parasitic infection. The aims of this study were to assess the feasibility of applying the 51Cr-EDTA absorption test for the assessment of intestinal permeability in the horse, and to apply this test in horses with experimentally induced alterations in gastrointestinal function. Four healthy ponies were administered 36 MBq of 51Cr-EDTA via naso-gastric tube, and urine samples were collected into polythene bags strapped to the pony's abdomen. Total urine voided every 6 h was collected during each test, and 1 ml samples were taken for measurement of gamma-radiation. Urinary recovery of 51Cr-EDTA was measured following intravenous atropine sulphate or bethanecol, and following 22 and 46 days of administration of 250,000 third-stage cyathostome larvae. There was no significant difference in urinary 51Cr-EDTA recovery following the control treatment, and following atropine or bethanecol administration, but significant increases were detected in the animals with experimental cyathostome infection consistent with increased permeability of the intestinal membrane. Motility modifying agents (bethanecol and atropine) did not affect absorption of 51Cr-EDTA, suggesting that subtle changes in motility might not affect the ability of this test to detect altered intestinal permeability. The finding of increased urinary recovery of 51Cr-EDTA in ponies with cyathostome infection suggests that 51Cr-EDTA may be a useful marker for assessment of intestinal permeability in the horse.

51Cr-EDTA absorption blood test: an easy method for assessing small intestinal permeability in dogs.

The 51Cr-EDTA test is a valuable clinical tool for screening intestinal diseases in dogs. The test is performed by calculating the percentage of recovery from urine of a PO-ingested dose of 51Cr-EDTA after 6 or 24 hours. Careful urine collection is a practical limitation of this test in dogs, and our goal was to develop a simpler test that measures 51Cr-EDTA in blood. A 51Cr-EDTA absorption test was simultaneously performed on urine and serum 43 times in healthy Beagle Dogs. Timed blood samples were withdrawn, and urine was collected during a 6-hour period. Percentages of the ingested dose were then calculated in urine and serum. The mean +/- standard deviation (range) percentage in urine after 6 hours was 14.07 +/- 8.72% (3.81-34.18%), whereas results in serum from samples taken at 2, 3, 4, 5, and 6 hours were 0.49 +/- 0.45% (0.02-2.13%), 0.75 +/- 0.52% (0.03-1.89%), 0.82 +/- 0.57% (0.13-2.21%), 0.70 +/- 0.53% (0.12-1.99%), and 0.47 +/- 0.44% (0.11-1.79%), respectively. The results for blood specimens showed good concordance with those for urine, especially for the samples taken at 4 hours (r = 0.89). Moreover, the correlation between urine and blood was better when the sum of the percentages of the recovered analyte from various blood samples was compared with urine. The correlation coefficient when summing 4 blood samples was excellent (r = 0.97) and remained excellent when summing only 2 blood samples taken at 3 and 5 hours (r = 0.95) or at 3 and 4 hours (r = 0.94). We conclude that a serum 51Cr-EDTA test determined by summing successive blood samples provides an easier means of estimating small intestinal permeability in dogs and gives results comparable to those of the 6-hour urine test.

In vivo influence of nicotine on human basal and NSAID-induced gut barrier function.

BACKGROUND: Smoking reduces the non-steroidal anti-inflammatory drug (NSAID)-induced small intestinal permeability increase in healthy people. It also affects inflammatory bowel disease that is associated with a disturbed gut barrier function. To assess the role of nicotine on barrier function, its influence on basal and NSAID-induced intestinal permeability was studied in healthy volunteers. METHODS: Thirty-one healthy non-smoker subjects performed permeability tests with 51Cr-EDTA and sugar markers (sucrose, lactulose, mannitol, sucralose) before and during 2 weeks of nicotine patch application, and with and without indomethacin intake, respectively. Since smoking has been described as affecting motility, transit measurements were also done with the sodium[13C]-octanoate and lactose-[13C]-ureide breath tests before and during nicotine exposure. Correlations between permeability markers were checked and the influence of gastrointestinal transit was assessed. RESULTS: Nicotine did not affect barrier function in vivo, nor gastric emptying, small-bowel transit time or orocaecal transit. 51Cr-EDTA and lactulose correlated in basal 0-6 h permeability testing (r = 0.529, P < 0.0001), as did 6-24 h excretion of 51Cr-EDTA and sucralose (r = 0.474, P < 0.001); 97% and 90% of the subjects had a permeability increase after indomethacin intake for 0-6 h and 6-24 h excretion of Cr-EDTA, respectively. This population proportion is 63% for lactulose/mannitol and 83% for sucralose. CONCLUSIONS: Short-term exposure to nicotine does not alter normal basal or NSAID-induced gut barrier function or transit. 51Cr-EDTA and the respective sugar markers correlate well in in vivo permeability testing in healthy humans. The radioactive test detects more NSAID-induced permeability increase than does the lactulose/mannitol ratio permeability test.

Conventional measurements of GFR using 51Cr-EDTA overestimate true renal clearance by 10 percent.

It is widely believed that measurement of the area under the plasma clearance curve (AUC) following a single intravenous injection of chromium-51 labelled ethylene diamine tetra-acetic acid ((51)Cr-EDTA) is a gold standard method for determining glomerular filtration rate (GFR). However, there are reports that (51)Cr-EDTA may have a significant extrarenal clearance. The aim of this study was to identify the non-renal component of (51)Cr-EDTA plasma clearance contributing to the AUC measurement of GFR. Seventy healthy postmenopausal women (mean age 60 years, range 45-79 years) were injected with 3 MBq (51)Cr-EDTA and 0.25 MBq iodine-125 labelled human serum albumin and 11 blood samples taken between 0 and 4 h through an indwelling venous cannula. For the first 21 subjects, two complete urine collections were made 0-2 h and 2-4 h after injection, and for the final 49 patients, four 1-h urine collections were made. The mean (51)Cr-EDTA total plasma clearance was 84 ml/min (range 50-132 ml/min). The mean ratio (SEM) of urine to total clearance determined from the cumulative 1-, 2-, 3- and 4-h data was 0.903 (0.018), 0.891 (0.013), 0.898 (0.011) and 0.899 (0.010) respectively and remained constant despite the mean urine concentration decreasing from 122% to 15%/litre during this period. A least squares fit to data from the 238 individual urine collections was used to determine the fraction of the total plasma clearance attributable to renal clearance, alpha(0), and the residual urine volume, delta V. The results were alpha(0)=0.910 (95% CI: 0.889-0.932) and delta V=14 ml (95% CI: -4 to +34 ml). The overestimation of the true renal clearance of (51)Cr-EDTA by the AUC method is believed to be due to the failure of the plasma clearance curve to reach the true terminal exponential by 2 h after injection as usually assumed. As a result, conventional measurements of GFR using (51)Cr-EDTA overestimate the true renal clearance of tracer by approximately 10%.

Intestinal permeability in strongyloidiasis.

The objective of the present study was to assess intestinal permeability in patients with infection caused by Strongyloides stercoralis. Twenty-six patients (16 women and 10 men), mean age 45.9, with a diagnosis of strongyloidiasis were evaluated. For comparison, 25 healthy volunteers (18 women and 7 men), mean age 44.9, without digestive disorders or intestinal parasites served as normal controls. Intestinal permeability was measured on the basis of urinary radioactivity levels during the 24 h following oral administration of chromium-labeled ethylenediaminetetraacetic acid ((51)Cr-EDTA) expressed as percentage of the ingested dose. The urinary excretion of (51)Cr-EDTA was significantly reduced in patients with strongyloidiasis compared to controls (1.60 +/- 0.74 and 3.10 +/- 1.40, respectively, P = 0.0001). Intestinal permeability is diminished in strongyloidiasis. Abnormalities in mucus secretion and intestinal motility and loss of macromolecules could explain the impaired intestinal permeability.

Intestinal permeability in strongyloidiasis

The objective of the present study was to assess intestinal permeability in patients with infection caused by Strongyloides stercoralis. Twenty-six patients (16 women and 10 men), mean age 45.9, with a diagnosis of strongyloidiasis were evaluated. For comparison, 25 healthy volunteers (18 women and 7 men), mean age 44.9, without digestive disorders or intestinal parasites served as normal controls. Intestinal permeability was measured on the basis of urinary radioactivity levels during the 24 h following oral administration of chromium-labeled ethylenediaminetetraacetic acid (51Cr-EDTA) expressed as percentage of the ingested dose. The urinary excretion of 51Cr-EDTA was significantly reduced in patients with strongyloidiasis compared to controls (1.60 + or - 0.74 and 3.10 + or - 1.40, respectively, P = 0.0001). Intestinal permeability is diminished in strongyloidiasis. Abnormalities in mucus secretion and intestinal motility and loss of macromolecules could explain the impaired intestinal permeability

A simple method for measuring severely reduced glomerular filtration rate.

OBJECTIVE: The purpose of this study was to develop a simpler method to measure severely reduced glomerular filtration rate (GFR) for patients with a GFR below 30 mL/min. METHOD: The GFR was measured in 24 patients using both the 51Cr EDTA slope-intercept method (the conventional method) and 99mTc-DTPA with our proposed simpler GFRn method. RESULTS: The correlation coefficient was 0.92 between the 2 methods, with a slope of 0.97 and an intercept of 2 mL/min. CONCLUSION: Our simplified method for measuring GFR is accurate for most patients with severely reduced GFR. Errors are acceptably small in patients with severely reduced GFR when edema or dehydration are present. If extrarenal (liver) clearance is significant, however, a urine sampling method is required for an accurate GFR measurement.

Evaluation of gastrointestinal toxicity of ibuprofen using surrogate markers in rats: effect of formulation and route of administration.

OBJECTIVE: To elucidate the mechanism of gastrointestinal (GI) toxicity of ibuprofen and to examine the effect of altered site of drug release using gastroduodenal and intestinal permeability tests in the rat model. METHODS: Adult male Sprague-Dawley rats were administered (n = 6 per group) either: (1) 100 mg/kg immediate or sustained release ibuprofen; (2) 100 mg/kg immediate release and ibuprofen lysinate; or (3) 100 mg/kg or 200 mg/kg ibuprofen po or s.c. Upper and lower GI permeability as a surrogate marker of toxicity were determined at pre-determined times using the urinary excretion of orally administered sucrose and 51Cr-EDTA permeability probes, respectively. RESULTS: Ibuprofen administration resulted in a dose-dependent increase in both upper and lower permeability of the GI tract. Both immediate and sustained release preparations of ibuprofen increased upper and lower GI permeability with no shift of toxicity to the site of drug release. Ibuprofen lysinate also induced significant increased upper and lower GI permeability comparable to immediate release ibuprofen. Oral doses were not more toxic than s.c. doses. CONCLUSION: Ibuprofen-induced increased GI permeable appears to be independent of the type of formulation and route of administration. This indicates that, contrary to some other nonsteroidal anti-inflammatory drugs, ibuprofen's effect on GI permeability is mainly systemic and the direct local effect contributes minimally to its overall GI toxicity. Ibuprofen may be a suitable candidate for sustained release formulations since its effect may be prolonged without the danger of a shift of side effect from the upper to the lower GI tract.

Interleukin-1alpha-induced changes in chromium-51 absorption, tissue retention, and urinary excretion in rats.

The effects of interleukin-1 alpha (IL-1alpha) on chromium-51 absorption, tissue retention, and urinary excretion were studied in adult male Sprague-Dawley rats. Ten rats were deprived of food for 12 h, injected intraperitoneally with mouse recombinant IL-1alpha (1 microg/kg of body weight in phosphate-buffered saline [PBS]) or control (0.1% bovine serum albumin [BSA] in PBS). Two hours after dosing with the IL-1alpha, rats were fed 50 microL (200 microCi, 0.36 microg Cr) of 51CrCl3 by micropipet. Blood was collected from the tail at 0.25, 0.5, 1, 2, and 4 h. Six hours after dosing with 51CrCl3, rats were exsanguinated and blood and tissues were sampled. The IL-1alpha significantly decreased chromium-51 in blood, urine, and some tissues compared to the control. The decreased absorption, retention, and urinary excretion of chromium-51 from 51CrCl3 in this study may be due to IL-1alpha-mediated increases in the production of prostaglandins and/or decreased production of gastric acid.

Absorçäo de líquido de irrigaçäo na ressecçäo transuretral da próstata em cäes / Irrigating fluid absorption during transurethral resection of the prostate in dogs

Trinta e dois cäes submetidos a entubaçäo do ducto torácico e cateterismo bilateral dos ureteres, foram divididos em 3 grupos: A- 4 cäes inoculados com RISA 131 I ou EDTA 51 Cr por via intravenosa ou peri-prostática; B- controle de 8 cäes submetidos a irrigaçäo vesical e prostática com 8 litros de glicina a 1,2 por cento contendo os marcadores radioativos; C- 8 cäes manejados como em B mas sujeitos à RTU da próstata. Os cäes foram acompanhados por 5 horas. A absorçäo de líquido de irrigaçäo foi calculada pelos métodos volumétrico e radioisotópico. Em 5 horas, 97 por cento da RISA 131 I inoculada via intravenosa permanecia neste espaço enquanto apenas 4,6 por cento da injetada no espaço peri-prostático penetrou no compartimento vascular. Para o EDTA 51 Cr, 63,6 por cento da massa inoculada no espaço peri-prostático foi recuperada na urina após 5 horas. O método volumétrico mostrou absorçäo média de 22,7 ml no grupo B e 276 ml no C, e o radioisotópico de 6,3 ml e 165,4 ml, respectivamente. O modelo experimental tem similaridades com o ser humano

Aumento da permeabilidade intestinal ao 51Cr-EDTA em crianças com diarréia persistente / Increased intestinal permeability to 51Cr-EDTA among children with persistent diarrhea

A diarréia persistente, uma condiçäo altamente prevalente em países em desenvolvimento, ocasiona diferentes alteraçöes morfológicas e funcionais na mucosa do intestino delgado, incluindo aumento da permeabilidade a diversas moléculas de prova. Investiga-se, pela primeira vez, a permeabilidade intestinal ao Cr-EDTA em crianças brasileiras com diarréia persistente. O teste de absorçäo do Cr-EDTA foi realizado em 13 crianças controle e em 14 com diarréia persistente, oferecendo-se 50 µCi da substância teste, por via oral, com posterior detecçäo da radioatividade excretada na urina de 24 horas. Houve diferença estatisticamente significante entre o grupo controle (mediana = 1,26 variaçäo = 0,20-3,31 por cento) e com diarréia persistente (mediana = 4,68; variaçäo = 1,40-10,29 por cento). Estabelecendo como padräo de referência de normalidade para o teste de absorçäo urinária de Cr-EDTA os valores mínimo e máximo encontrados no grupo controle, observaram-se que 61,5 por cento dos pacientes com diarréia persistente apresentaram resultado alterados. Nos pacientes com diarréia persistente, a excreçäo do Cr-EDTA foi significativamente maior no grupo que fez uso de dieta à base de hidrolisado protéico e/ou nutriçäo parenteral total, em comparaçäo com o que näo fez, demonstrando sua possível utilidade como indicador de gravidade. Em quatro pacientes com diarréia persistente, o teste foi realizado após a recuperaçäo clínica, sendo que houve queda nos valores de excreçäo em todos os casos. A partir destes dados, pode-se concluir que: 1) na diarréia persistente deve haver alteraçäo na permeabilidade intestinal, que permitiria a entrada aumentada de antígenos alimentares locais, com subseqüente sensibilizaçäo e enteropatia alérgica, contribuindo para a perpetuaçäo do ciclo de diarréia, má absorçäo e desnutriçäo; 2) o teste do Cr-EDTA pode ser útil como indicador de gravidade na diarréia persistente; 3) a alteraçäo da permeabilidade intestinal é um fenômeno secundário na diarréia persistente e, com a reconstruçäo da barreira intestinal, ocorre normalizaçäo da mesma.

[Increased intestinal permeability to 51 Cr-EDTA among children with persistent diarrhea]. / Aumento da permeabilidade intestinal ao 51Cr-EDTA em crianças com diarréia persistente.

Persistent diarrhea, a condition highly prevalent in developing countries, causes different morphological and functional alterations of the mucosa of the small intestine, including increased permeability to different test molecules. In the present study we investigate for the first time the intestinal permeability to 51Cr-EDTA of Brazilian children with persistent diarrhea. The test of 51Cr-EDTA absorption was performed in 13 control children and in 14 children with persistent diarrhea by offering 50 microCi of the test substance by the oral route, with later detection of radioactivity excreted in 24-hour urine. There was a statistically significant difference between the control group (median = 1.26; range = 0.20-3.31%) and the group with persistent diarrhea (median = 4.68; range = 1.40-10.29%). Using the minimum and maximum values detected in the control group as the normal reference standard for the test of urinary 51Cr-EDTA absorption, we observed that 61.5% of the patients with persistent diarrhea showed altered results. Among the patients with persistent diarrhea, 51Cr-EDTA excretion was significantly higher in the group fed a protein hydrolysate diet and/or total parenteral nutrition than in the group that did not receive this diet. In four patients with persistent diarrhea, the test was performed after clinical recovery, with a fall in the excretion levels in all cases. On the basis of these data, we may conclude that: 1) in persistent diarrhea there must be alteration of intestinal permeability that might permit an increased entry of local alimentary antigens, with subsequent sensitization and allergic enteropathy, contributing to the perpetuation of the diarrhea, malabsorption and malnutrition cycle; 2) the 51Cr-EDTA test may be useful as an indicator of severity in persistent diarrhea; 3) alteration of intestinal permeability is a secondary phenomenon in persistent diarrhea, with normalization occurring after reconstruction of the intestinal barrier.

Comparison between the lactulose/mannitol and 51Cr-ethylenediaminetetraacetic acid/14C-mannitol methods for intestinal permeability. Frequency distribution pattern and variability of markers and marker ratios in healthy subjects.

Urinary excretion of lactulose and mannitol, determined by gas-liquid chromatography, was compared with that of 51Cr-ethylenediaminetetraacetic acid (EDTA) and 14C-mannitol for measurement of intestinal permeability in 28 healthy humans. The 0- to 6-h excretion values for unlabelled and labelled mannitol (marker of transcellular permeability) were normally distributed, whereas excretion values for lactulose and 51Cr-EDTA (markers of paracellular permeability) were skewly distributed, as were the lactulose to mannitol and 51Cr-EDTA to 14C-mannitol ratios. Excretion of the transcellular markers but not of the paracellular markers was significantly correlated to urinary volume; correction for urinary volume resulted in decreased test variability. Significant correlation was found between lactulose and 51Cr-EDTA excretion (p < 0.01) and between mannitol and 14C-mannitol excretion (p < 0.001) but not between the lactulose to mannitol and 51Cr-EDTA to 14C-mannitol ratios (p = 0.11). Inter- and intraindividual test variability was greater for each chemically determined marker than for the corresponding isotope-labelled marker. Similarly, variability was greater for each paracellular marker than for the corresponding transcellular marker and for each paracellular/transcellular marker ratio than for the transcellular marker alone. Variability of mannitol excretion was increased by the frequent presence of food-derived mannitol in the urine.

In vivo cross-match by chromium-51 urinary excretion from labeled erythrocytes: a case of anti-Gerbich.

We studied a patient with an alloantibody to the high-frequency red blood cell (RBC) antigen Gerbich. A nationwide search for rare Gerbich-negative blood (less than 1:45,000 donors) located only seven units, and our supply was quickly exhausted. By using an in vivo cross-matching method, we demonstrated that this anti-Gerbich did not cause RBC destruction. Regular Gerbich-positive transfusions could then proceed without hemolysis. This cross-match test was based on the determination of the urinary excretion rates of injected radioactive chromium-labeled donor erythrocytes by which it was possible to determine compatibility only 24 hr after the test was begun. The procedure provides an easy and accurate means for in vivo cross-matching of conventionally incompatible donor blood.