Glycosylated hemoglobin in dogs: precision, stability, and diagnostic utility

The precision and stability of the ion exchange chromatography assay for canine glycosylated hemoglobin (HbA(1)) were examined. The coefficient of variation (CV) of within-run replicate assays was 1.3 to 2.6%; the CV of between-run duplicate assays was 3.1%. The mean HbA(1) content in 44 healthy dogs was 7.1% (SD = 1.1%, range = 5.1-9.7%). Paired aliquots of 12 blood samples were stored at 4 degrees C and 25 degrees C, and HbA(1) was measured on the day of collection and at 3, 5, and 7 days after collection. In the blood stored at 4 degrees C, no significant increase in the HbA(1) content was seen. No significant increase in HbA(1) content was found in the blood stored at 25 degrees C after 3 days, but dramatic increases were observed after 5 and 7 days of storage. No significant difference was observed in the HbA1 content in heart blood collected 18 hours after death from 9 dogs kept at 25 degrees C. The HbA(1) content was measured in 10 hospitalized diabetic dogs. Five of the dogs had received no insulin and all 5 had elevated HbA(1) values. The other 5 dogs had received insulin for 1 to 9 months; 2 of the 5 had increased HbA(1) content. The HbA(1) content was determined periodically for 9 months in one diabetic dog and it declined from 14% to 8.2%.     

Ion-exchange microchromatography and thiobarbituric acid colorimetry for the measurement of canine glycated hemoglobins

Nonenzymatic glycation of hemoglobin is a slow, continuous, and irreversible process which takes place during the whole lifespan of the erythrocyte. When hemolytic diseases are ruled out, the levels of glycated hemoglobins reflect the time-averaged serum glucose concentration for the preceding weeks. Canine hemoglobin also binds physiologically to intraerythrocytic glucose to form a glycated fraction which provides information on the animal's long-term glycemic status. This study describes an overall evaluation of ion-exchange microchromatography and thiobarbituric acid (TBA) colorimetry for the measurement of canine glycated hemoglobins. The intra- and inter-assay coefficients of variation (CVs) found were less than 5% in normal and diabetic canine samples, and both assays proved linear over the analytical range tested, which was wide enough to include the expected clinical values. Under our laboratory's conditions, the reference range for HbA(1) was 5.82 +/- 0.62% and for HbA(1)c was 2.35 -/+ 0.47%. Sample stability was lower using the ion-exchange procedure, with increases in HbA(1) observed after 4 days in whole blood and hemolysates stored at room temperature, after 12 days in whole blood stored at 4 degrees C, and after 7 days in hemolysates stored at 4 degrees C and -20 degrees C. In the case of TBA colorimetry, whole blood was stable for at least 21 days at room temperature and at 4 degrees C, and hemolysates were stable for 18 days at room temperature, at least 21 days at 4 degrees C, and up to 3 months at -20 degrees C.     

Evaluation of two point-of-care analysers for measurement of fructosamine or haemoglobin A1c in dogs

Measurement of glycosylated proteins such as fructosamine and haemoglobin A1c (HbA1c) can be used to assess glycaemic control in canine diabetic patients. Two point-of-care analysers, designed for human diabetics, were evaluated for use in dogs. Blood samples were collected from 50 normoglycaemic dogs, 100 diabetic patients and five dogs with insulinoma and tested using the In Charge fructosamine meter and the Haemaquant/Glycosal HbA1c meter. Readings were obtained in all cases except for 21 of 50 diabetics, which were above the upper limit of the In Charge meter. Diabetic dogs had higher fructosamine and HbA1c concentrations compared to controls. However, there was poor agreement between the In Charge meter readings and serum fructosamine concentrations, suggesting that there are problems associated with the use of this device in dogs. HbA1c concentrations showed a high degree of correlation with glycosylated haemoglobin measured at an external laboratory, suggesting that the Haemaquant/Glycosal meter warrants further evaluation for veterinary use.     

Fructosamine and glycated hemoglobin in the assessment of glycaemic control in dogs

Fructosamine and glycated hemoglobin (HbA1c) concentrations were measured simultaneously in 222 dogs (96 healthy and 126 sick dogs). The dogs were divided into 3 groups according to the glucose concentration: hypo, hyper and euglycaemic dogs. Serum fructosamine concentrations were measured by the reduction test with nitroblue tetrazolium. A turbidimetric inhibition immunoassay and specific polyclonal antibodies were used to evaluate glycated hemoglobin concentrations. A significant correlation was found between glucose concentration and either fructosamine (r = 0.63, p < 0.0001) or glycated hemoglobin (r = 0.82, p < 0.0001). The correlation was higher in hyperglycaemic dogs for fructosamine (r = 0.80, p < 0.0001) and in hypoglycaemic dogs for glycated hemoglobin (r = 0.91, p < 0.005). We found a significant correlation between serum fructosamine and glycated hemoglobin (r = 0.65, p < 0.0001 ) when all the dogs were studied. A significant correlation was observed between serum fructosamine and glycated hemoglobin only in hyperglycaemic dogs (r = 0.82, p < 0.0003). Thus, fructosamine and HbA1c may be considered for use in screening tests for diabetes mellitus in dogs and clinical tests for monitoring control and evaluation of the diabetic animal's response to treatment. The choice of the analytical assay depends on the characteristic and analytical opportunities of the laboratory, as well as the number of serum samples to be analysed.     

Thyroid and immunologic status of dogs with perianal fistula

Lymphocyte-proliferation responses, absolute lymphocyte counts, and thyrotropin-stimulation responses were determined in 33 dogs with perianal fistula; serum immunoglobulin values also were determined in 15 of the 33 dogs. Lymphocytes were stimulated with concanavalin A, pokeweed mitogen, and phytohemagglutinin and were cultured with medium containing normal pooled canine serum or fresh patient's autologous serum. Initially, lymphocytes from 9 dogs (27.3%) had depressed stimulation responses to greater than or equal to 1 phytomitogen, and 4 of the 9 dogs had absolute lymphopenia. One month after recovery in these 9 dogs, lymphocytes from 4 dogs (66.7%) had normal proliferation responses. Of immunoglobulin determinations in 15 dogs, serum IgA values were 32 to 185 mg/dl (mean, 69 +/- 10 mg/dl) and were low in 2 dogs (13%), and serum IgM values were 48 to 610 mg/dl (mean, 263 to 46 mg/dl) and were high in 8 dogs (53%). Serum IgG values were 1,050 to 3,220 mg/dl (mean, 2,339 +/- 165 mg/dl) and were high in 10 dogs (71%). After thyrotropin stimulation, 1 dog was considered hypothyroid. Neither pathogenesis nor prognosis of canine perianal fistula was clarified via immunoglobulin concentrations or absolute lymphocyte counts. Based on lymphocyte-proliferation assays, suppression of cell-mediated immunity was probably a result of perianal fistula, rather than a cause of the fistula.     

Testicular superoxide dismutase activity, heat shock protein 70 concentration and blood plasma inhibin-alpha concentration of dogs with a Sertoli cell tumor in a unilateral cryptorchid testis

The proportions of Sertoli cell tumor (SCT), seminoma and Leydig cell tumor in 50 dogs with unilateral testicular tumors were 52%, 36% and 12%, respectively. The rate of occurrence of SCT in the cryptorchid testis was very high (71%). The testicular superoxide dismutase (SOD) activity, testicular heat shock protein (HSP) 70 concentration and peripheral blood plasma inhibin (INH)-alpha concentration of 10 dogs with a unilateral cryptorchid testis and no testicular tumors, 10 dogs with SCT in a unilateral cryptorchid testis and 10 normal dogs, all aged 5-15 years, were measured in order to identify high risk factors for the occurrence of SCT in the canine cryptorchid testis. The mean SOD activity in cryptorchid testes and SCTs was significantly lower and higher, respectively, than in normal testes (both P<0.01). The mean HSP 70 concentration in both cryptorchid testes and SCTs was significantly higher than in normal testes (both P<0.01). The mean plasma INH-alpha concentration of the cryptorchid and SCT dogs was significantly lower and higher, respectively, than in normal dogs (P<0.05 and 0.01, respectively). The low SOD activity in the cryptorchid testis, low blood plasma INH-alpha concentration of the cryptorchid dogs and high HSP 70 concentration in the SCTs may be related to the occurrence of SCT and tumor cell proliferation in canine cryptorchid testes.     

Glycosylated hemoglobin measurement in dogs and cats: implications for its utility in diabetic monitoring

The measurement of glycosylated hemoglobin (HbA₁) levels in humans is used to indicate the degree of long-term diabetic control. Using a commercially available kit for human HbA₁, values were obtained for normal and diabetic dogs and cats. The normal range established in dogs was broad and overlapped considerably with the range in diabetics. Under the assay conditions and with a limited number of diabetic animals, the test was not found to be of value for dogs or cats.     

Efficacy and safety of allogenic canine adipose tissue-derived mesenchymal stem cell therapy for insulin-dependent diabetes mellitus in four dogs: A pilot study

Mesenchymal stem cells (MSCs) possess regenerative and immunomodulatory properties and can control the immune dysregulation that leads to β-cell destruction. Stem-cell transplantation could thus manage insulin-dependent diabetes mellitus (IDDM) in dogs. In this pilot study, we aimed to assess canine adipose tissue-derived MSCs (cAT-MSCs) transplantation as a treatment for canine diabetes mellitus. This study included four dogs with over a year of insulin treatment for IDDM, following diagnosis at the Veterinary Medicine Teaching Hospital of Seoul National University. Allogenic cAT-MSCs were infused intravenously three or five times monthly to dogs with IDDM. Blood and urine samples were obtained monthly. General clinical symptoms, including changes in body weight, vitality, appetite, and water intake were assessed. Three of the four owners observed improvement of vitality after stem cell treatment. Two of the four dogs showed improvement in appetite and body weight, polyuria, and polydipsia. C-peptide has increased by about 5–15% in three of the cases, and fructosamine and HbA1c levels have improved in two of the cases. Hyperlipidemia was resolved in two of the dogs, and there was no concurrent bacterial cystitis in any of the dogs. C-peptide secretion and lipid metabolism are associated with diabetic complications. Improvement in these parameters following the treatment suggests that cAT-MSC transplantation in dogs with IDDM might help to improve their insulin secretory capacity and prevent diabetic complications.     

Evaluation of a Portable Meter to Measure Ketonemia and Comparison with Ketonuria for the Diagnosis of Canine Diabetic Ketoacidosis

Background: The diagnosis of canine diabetic ketoacidosis (DKA) usually is based on measurement of urinary acetoacetate (ketonuria). In humans, this test is less sensitive and specific than blood 3-β-hydroxybutyrate (ketonemia) evaluation.
Hypothesis: Ketonemia measurement using a portable meter is more accurate than ketonuria determination with a dipstick to diagnose canine DKA.
Animals: Seventy-two client-owned diabetic dogs with ketonemia, ketonuria, or both.
Methods: Prospective observational study. Based on blood bicarbonate concentration and anion gap, dogs were divided into 2 groups: patients with DKA ( n = 25); patients with diabetic ketosis ( n = 47). Sensitivity, specificity, and positive and negative likelihood ratio (LR) at different cut-off points were determined for both ketonemia and ketonuria. Receiver operating characteristic (ROC) analysis was used to assess the accuracy of each diagnostic test to diagnose DKA.
Results: With regard to ketonemia, cut-off values of 2.3 and 4.3 mmol/L revealed 100% sensitivity and 100% specificity, respectively, whereas cut-off values of 2.8 and 3.5 mmol/L showed a −LR of 0.05 and a + LR of 13.16, respectively. With regard to ketonuria, a cut-off value of 1+ revealed 92% sensitivity, 40% specificity, and −LR of 0.20, whereas a cut-off value of 3+ revealed 44% sensitivity, 94% specificity, and +LR of 6.89. The areas under the ROC curves for the ketonemia and ketonuria tests were significantly different (0.97 and 0.81, respectively, P = .003).
Conclusions and Clinical Importance: Measurement of ketonemia is accurate and more effective than measurement of ketonuria to diagnose canine DKA.     

Anti-insulin antibodies in diabetic dogs before and after treatment with different insulin preparations

Background: Anti‐insulin antibodies (AIA) occur in diabetic dogs after insulin therapy, although their clinical significance is unclear. Hypothesis: Treatment of diabetic dogs with heterologous insulin is more likely to stimulate production of AIA than is treatment with homologous insulin. Animals: Diabetic dogs sampled before insulin therapy (n = 40), diabetic dogs sampled following treatment with porcine (homologous) insulin (n = 100), bovine (heterologous) lente insulin (n = 100), or bovine protamine zinc (PZI) insulin (n = 20), and nondiabetic control dogs (n = 120). Methods: Prospective observational study. Sera were analyzed by ELISA for antibodies against porcine insulin, bovine insulin, insulin A, B, or C peptides, and control antigens; canine distemper virus (CDV) and canine thyroglobulin (TG). Canine isotype‐specific antibodies were used to determine total and anti‐insulin IgG1 : IgG2 ratios. Results: There was no difference in CDV or TG reactivity among the groups. AIA were detected in 5 of 40 newly diagnosed (untreated) diabetic dogs. There was no significant difference in AIA (ELISA optical density reactivity) comparing control and porcine insulin‐treated diabetic dogs (P > .05). Anti‐insulin reactivity was most prevalent in bovine PZI insulin‐treated dogs (90%; P < .01), and bovine lente insulin‐treated dogs (56%; P < .01). AIA induced by treatment were enriched for the IgG1 isotype. Conclusions and Clinical Importance: This study indicates that bovine insulin is more immunogenic than porcine insulin when used for treatment of diabetic dogs.     

Hematological changes during the course of canine babesiosis caused by large Babesia in domestic dogs in Warsaw (Poland)

In the presented study we evaluated the hematological changes in samples of blood obtained from 248 dogs naturally infected with large Babesia. The evaluation included red blood cell count, hemoglobin concentration, hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), leucocyte counts, thrombocyte counts, mean platelet volume (MPV), morphology of erythrocytes and leucogram. The most common disorders in affected dogs were thrombocytopenia and anisocytosis. The count of erythrocytes below reference values was detected in 26.2% of dogs and 31.4% of affected animals presented hematocrit below the reference values. Hemoglobin concentration below the reference values was noted in 29% of dogs, an increase of MCHC above normal values was detected in 21% of examinated dogs and MCV below normal values was recognized in 2% of dogs. 60.5% of dogs presented anisocytosis, 25% poikilocytosis, 23.8% polychromasia, 19.7% hypochromia and 4.4% erythroblastosis. Thrombocytopenia was detected in 99.5% of dogs, but only 15.3% of examined animals showed increase of MPV, which suggests a response of the bone marrow. 36.3% of dogs had neutropenia, and 21.8% presented a left shift, 14.9% had the lymphocytosis and 7.2% lymphopenia.     

QUANTITATIVE99mTc-PERTECHNETATE THYROID SCINTIGRAPHY IN NORMAL BEAGLES

This study was done to investigate the validity of published canine thyroid/salivary (TS) rations of approximately i in normal dogs and to detemine thyroid uptak of ^99mTc-pertechnetate (pertechnetate) measured as percent uptake of injected dose. These parameters were evaluated in 13 Beagle dogs over a 4 hour period. Mean ± standard deviation (SD) and median T/S ratios of 1.2 ± 0.3 and 1.1 were essentially the same at twenty minutes and 1 hour. T/S Values ranged from 0.9 to 2.2 at 20minutes and from 0.8 to 2.4 at 1 hour. T/S ratio values progressively declined over the subsequent time intervals with mean ± SD and median values of 0.6 ± 0.2 and 0.6, respectively, measured at 4 hour. The mean with a rang of 0.28% to 0.90%. The mean ± SD time interval from injection of pertechanetate to maximum uptake within the thyroid gland was 160 ± 55 minutes with a range 31–240 minutes. The data derived from this study of normal dogs may be useful in the evaluation of dogs with thyroidal diseases including hypthyroidism     

Vascular endothelial growth factor in diabetic and nondiabetic canine cataract patients

Objective To measure vascular endothelial growth factor (VEGF) levels in aqueous humor, serum, and plasma in diabetic and nondiabetic cataractous dogs. Methods Canine VEGF was assayed in the plasma and serum of 32 dogs (20 diabetics; 12 nondiabetics) and aqueous humor in 57 eyes of those dogs (39 diabetic; 18 nondiabetic) undergoing phacoemulsification, using a commercial canine VEGF assay. Statistical analysis was performed using Fisher’s PLSD, t‐test, and regression analysis to compare values by diabetic status, duration of diabetes, age, weight, gender, left vs. right eye, and blood clarity. Results Plasma, but not serum or aqueous humor VEGF values of diabetics were significantly greater than nondiabetics (P = 0.019). Older nondiabetics (10–15 years) had higher plasma VEGF values than younger (0–5 and 5–10 years) dogs (P = 0.0002 and 0.0001, respectively). There was no significant difference in aqueous humor VEGF between left and right eyes in all patients. Serum and plasma, but not aqueous humor, VEGF values in females were significantly higher than males in both groups. Conclusion Similar to human diabetic patients, VEGF aqueous humor values in all dogs are significantly higher than blood values. Aqueous humor VEGF values in human diabetics are elevated and correlate with the severity of diabetic retinopathy. However, aqueous humor values of VEGF in diabetic dogs are not greater than nondiabetics and may serve to protect the dog against development of diabetic retinopathy.     

Keratoconjunctival effects of diabetes mellitus in dogs

OBJECTIVES: To compare Schirmer tear test (STT) values, corneal sensitivity, tear film break up times (TFBUTs), and tear glucose concentrations in relation to conjunctival microflora, and conjunctival cytologic and histologic findings among diabetic cataractous, nondiabetic cataractous, and nondiabetic noncataractous dogs. Procedures Fifteen dogs in each category underwent neuro-ophthalmic examination; aerobic, anaerobic and fungal conjunctival cultures; assessment of corneal touch threshold (CTT), STT, tear glucose, TFBUT; and conjunctival cytology and histology (in certain cases only). Degree of cataract and uveitis were critically graded. Glycemic control was estimated using serum fructosamine and glycosylated hemoglobin. RESULTS: STT values were significantly lower in diabetic cataractous than nondiabetic noncataractous dogs. CTT of diabetic cataractous dogs was significantly lower than that of nondiabetic noncataractous dogs. Mean TFBUTs were significantly less in diabetic cataractous dogs than nondiabetic cataractous and nondiabetic noncataractous dogs. Tear glucose concentrations were significantly higher in diabetic cataractous dogs than nondiabetic cataractous and nondiabetic noncataractous dogs. Conjunctival microbial isolates did not differ among groups. There were no significant differences in degree of cataract or uveitis between diabetic cataractous and nondiabetic cataractous groups. There was mild submucosal inflammatory infiltrate in conjunctival specimens from diabetic dogs. Conjunctival epithelial dysplasia and/or squamous metaplasia was/were detected in conjunctival biopsies of 5/7 diabetic dogs. Reductions in conjunctival goblet cell (GC) densities were noted in 4/7 diabetic dogs; there were no significant differences in mean GC densities among the three groups. CONCLUSIONS: Diabetic cataractous dogs have significantly altered keratoconjunctival characteristics compared to nondiabetic cataractous and nondiabetic noncataractous dogs.     

Detection of serum alpha-fetoprotein in dogs with hepatic tumors.

Serum alpha-fetoprotein (AFP) concentration was detected by use of 2 commercially available kits containing antibodies to human AFP--a radioimmunoassay and an enzymetric test. Using neonatal canine serum (a source high in AFP), it was determined that reagents from both kits were able to bind to canine AFP, but a significant difference was detected in AFP concentration. The enzymetric test was superior in detecting canine AFP. Sera from dogs were classified into 6 groups: from dogs with primary hepatic tumors only (group 1); from dogs with primary hepatic tumors and other tumors (group 2); from dogs with normal liver but with other types of neoplasia (group 3); from dogs with nonneoplastic hepatic disease and tumors originating in other organs (group 4); from dogs with nonneoplastic hepatic disease only (group 5); and from clinically normal dogs (group 6). Serum biochemical determinations (alkaline phosphatase, alanine transaminase, albumin, total protein, total bilirubin, and serum bile acids) and values from the 2 AFP assays were obtained for all dogs. Serum AFP concentration detected by the enzymetric test was significantly higher in dogs with hepatocellular carcinoma and cholangiocarcinoma. Values greater than 250 ng/ml were detected in 5 of 9 dogs with cholangiocarcinoma and in 3 of 4 dogs with hepatocellular carcinoma. High serum AFP concentration also was indicative of liver involvement in 2 of 3 dogs with primary hepatic lymphosarcoma; 2 dogs had values greater than 225 ng/ml. Serum AFP concentration in dogs with other types of hepatic tumors was less than 250 ng/ml, and serum AFP concentration could not be correlated with such tumors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of a disposable device for the measurement of haemoglobin A1c in dogs

A disposable device designed for measuring glycated haemoglobin (hba1c) in human blood was evaluated for use in dogs. edta blood samples were collected from 50 normoglycaemic dogs, 10 dogs suffering from anaemia and 112 diabetic dogs. hba1c was measured in all the dogs except for five of the diabetic animals, in which the concentrations were above the range of the device, that is, more than 13 per cent, and two of the anaemic dogs, in which they were below its limit of detection, that is less than 3 per cent. The diabetic dogs had higher hba1c values (range 4.9 to >13 per cent, median 9.3 per cent) than the normoglycaemic dogs (range 3.7 to 5.6 per cent, median 4.7 per cent). In the anaemic dogs the values were significantly lower (range <3.0 per cent to 5.2 per cent, median 3.5 per cent) than in the normoglycaemic dogs. There was a good correlation (R(2)=0.48) between the measurements obtained with the device and the measurements obtained with a system already validated for use in dogs.     

Evaluation of a commercial kit for measurement of glycosylated hemoglobin in canine blood

Total glycosylated hemoglobin (HbA(1)) was measured in canine blood samples by conventional macrocolumn ion exchange chromatography and with a commercial glycosylated hemoglobin kit. The two methods correlated well (r= 0.94, p < 0.001) and the reproducibility of the kit method was good. The commercial kit method is recommended for measurement of HbA(1) in canine blood.     

Microcytosis and Iron Status in Dogs With Surgically Induced Portosystemic Shunts

Microcytosis is common in dogs with congenital portosystemic shunts (PSS) and acquired liver disease. The objective of this study was to determine if microcytosis could be induced in normal dogs by surgical creation of PSS, and to characterize the changes in hematology and iron status. Hematocrit, mean cell volume, mean cell hemoglobin, and mean cell hemoglobin concentration decreased linearly from 45.5%. 69.1 fL, 22.8 g/dL and 33.1% to 39.5%. 55.9 fL, 17.8 g/dL and 31.9%. respectively, 18 weeks after creation of PSS. The erythrocyte count did not change, but red cell distribution widths indicated a shift to a heterogenous population with decreased volume. Mean cell volume and mean cell hemoglobin decreased rapidly after induction of PSS and were significantly ( P < .05) different from presurgery values within 2 weeks. Serum iron and copper concentrations and total iron binding capacity were decreased in dogs with PSS. Liver iron concentration doubled after creation of PSS, with the majority of stainable iron located in Kupffer cells. The changes in erythrocyte indices and measures of iron status in dogs with surgically induced PSS were similar to those in dogs with congenital PSS. Microcytosis developed rapidly in dogs after induction of PSS. These results indicate that iron deficiency was not the cause of microcytosis in these dogs.     

Computed tomographic features of the normal canine thyroid gland.

The computed tomographic (CT) features of the normal thyroid gland were compiled from images acquired in 25 client-owned dogs without thyroid gland disease. The mean pre- and postcontrast attenuation values were 107.5 and 169.0 Hounsfield Units, respectively. After injection of intravenous contrast medium (600 mg iodine/kg), the apparent thyroid gland volume (both lobes combined) increased from a mean value of 1148.0 nm3 to a mean value of 1188.9 mm3. All thyroid lobes were homogeneous on pre- and postcontrast images. In a craniocaudal direction, the gland spanned a region from the 1st to the 8th tracheal ring and the right lobe was often more cranial than the left. On transverse images the lobe shape was ovoid in 72%, and its location was dorsolateral to the trachea in 90% of dogs. Parathyroid glands could not be identified and an isthmus connecting both thyroid lobes was only seen in one dog. Considering the excellent visibility of the normal canine thyroid gland, CT can be beneficial in the differentiation of thyroidal versus nonthyroidal neck masses. CT also yields potential in the staging of thyroid carcinomas.     

Iron Status and Erythrocyte Volume in Dogs With Congenital Portosystemic Vascular Anomalies

Microcytosis, hypochromasia, and low mean corpuscular hemoglobin are frequent hematologic abnormalities in dogs with portosystemic vascular anomalies (PSVA). The relationship of iron status to these abnormalities is unclear. We evaluated iron status and hematologic and biochemical parameters in dogs with congenital PSVA before (25 dogs) and after (11 dogs) partial ligation of the vascular anomaly. Serum iron concentration and total iron binding capacity were subnormal in 56% and 20% of dogs with PSVA, respectively. Transferrin saturation was normal in 68%, decreased in 20%, and increased in 12% of the dogs. Plasma ferritin concentration was either normal (56%) or high (44%), and was not associated with increases in ceruloplasmin concentration. Hepatic stainable iron was increased in 10 of 16 dogs. Mean corpuscular volume (MCV), mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration were decreased in more than 60% of dogs with PSVA. Serum biochemical abnormalities included high bile acid concentration and alanine transaminase (ALT) and alkaline phosphatase (ALP) activities; and low urea, creatinine, cholesterol, and total protein concentrations. Serum iron concentration and clinical status (normal or PSVA) significantly influenced MCV ( P = .003 and P < .001, respectively), whereas age, ceruloplasmin, ferritin, cholesterol, bile acids, and total iron binding capacity did not. Partial ligation of PSVA was associated with resolution of clinical signs and the return to normal of iron status and all clinicopathologic abnormalities, except total fasting bile acid concentrations. These findings indicate that iron status is frequently abnormal in dogs with PSVA and that low serum iron concentration appears to be related to the development of microcytosis. The normalization of iron status and clinicopathologic abnormalities after treatment suggests that they are direct consequences of PSVA.