High performance liquid chromatography method for rapid and accurate determination of homocysteine in plasma and serum

Determination of homocysteine in plasma or serum for evaluation of cobalamin and folate deficiency is becoming an important diagnostic procedure. Accurate, rapid and low cost methods for measuring homocysteine are therefore required. We have improved an HPLC method and made it suitable for clinical application. The more important changes are the addition of an internal standard, mercaptopropionylglycine, and the use of a plasma/serum based calibration material. The method consists of the following steps: reduction of the sample with tri-n-butylphosphine, precipitation of proteins, derivatisation with ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulphonate, and HPLC separation followed by fluorescence detection. The linearity of the assays is established and the coefficient of variation is 3.0%. Stability studies show that blood samples must be cooled or centrifuged immediately after venipuncture. The method is useful for evaluation of cobalamin or folate deficiency, especially in patients with normal or moderately depressed cobalamin or folate concentrations in blood.

Coeliac disease, folic acid deficiency and epilepsy with cerebral calcifications

Two cases of focal occipital epilepsy with cerebral calcifications poorly responsive to antiepileptic treatment are described. In both cases coeliac disease was diagnosed and folic acid deficiency documented. A gluten-free diet and a brief supplementation with folic acid lead to a complete EEG and clinical normalization in one case and to a significant improvement of EEG and seizure control in the other.

Erythrocyte folate levels: a clinical study

PURPOSE

1) To determine if there are significant differences in laboratory parameters and patient characteristics between patients with low erythrocyte (RBC) folate levels and those with normal RBC folate levels; 2) to determine the correlation between serum and RBC folate levels; 3) to determine if the RBC folate level changed the diagnosis, treatment, and outcome of these patients if the serum folate level was available.

PATIENTS AND METHODS

The study is a retrospective review of all inpatients and outpatients at a public teaching hospital who had an RBC folate level less than or equal to 175 ng/ml (N = 57) over the study period (69 months) and a blindly selected group of patients with RBC folate levels greater than 175 ng/ml (N = 53) during the same period.

RESULTS

Patients with low RBC folate levels had higher mean corpuscular volume (MCV) and red cell distribution width (RDW) values and lower serum folate and B12 values than patients with normal RBC folate levels, but there was no difference in degree of anemia, presence of oval macrocytes and/or hypersegmented neutrophils on the peripheral blood smear, LDH, alcohol use, diet, or any other measured clinical parameter. Serum and RBC folate levels were highly correlated and a low RBC folate affected the clinical outcome of three patients (5% of the low RBC folate group).

CONCLUSIONS

Based upon these retrospective data and a review of the literature, we cannot define significant differences between patients with low RBC folate and randomly selected patients with normal RBC folate that could not have been equally well defined using serum folate values. The sensitivity and specificity of a low RBC folate level in the diagnosis of ill or healthy individuals are undefined, and until prospective studies utilizing some of the newer, more specific biochemical indicators of tissue folate are completed, the interpretation of low RBC folate levels will remain problematic.

Basic blue 75: a new stain for erythroblasts

C.I. basic blue 75 in an aqueous alkaline solution stains the nuclei of mature and immature erythroblasts bright red. Simultaneously, the stain colors the cytoplasm of erythroblasts blue in immature cells and purple in mature cells. Colors of the type described were not found in other normal and abnormal hematopoietic cells.

Neutrophil myeloperoxidase measurement uncovers masked megaloblastic anemia

We report the observation of a high neutrophil myeloperoxidase activity (MPXI) in patients with megaloblastic anemia. MPXI is rapidly measured as part of an automated complete blood count (Technicon H*1, Technicon Instruments Corp, Tarrytown NY). We describe the range of MPXI levels in healthy and patient populations and in 10 cases of megaloblastic anemia, including five having elevated mean cell volume (MCV) and five without macrocytosis. Regardless of the MCV, our megaloblastic patients had hypersegmented neutrophils and elevated MPXI levels without visible alteration of granule content. MPXI measurement may be particularly useful in identifying cases of "masked megaloblastic anemia" where the MCV is below 100 fL. The advantage of the MPXI over other methods of uncovering masked megaloblastic anemia is its simplicity when performed as part of a routine complete blood count on an automated hematology instrument.

Serum homocysteine in routine evaluation of potential vitamin B12 and folate deficiency

Total serum homocysteine (Hcy) was measured in patients with either low serum folate, low serum vitamin B12 (B12), or potential metabolic defects, in order to evaluate Hcy as an indicator of the tissue status of the two vitamins. An increased Hcy supported the diagnosis of frank tissue deficiency in those patients in whom tissue deficiency was evident by other means. A Hcy within the reference interval enabled the clinician to identify those patients whose low serum vitamin level and symptoms did not reflect a tissue deficiency of B12 or folate of clinical consequence. Children with inherited disturbances of B12 metabolism, and whose serum B12 was within the reference interval, were correctly identified by an increased Hcy. A declining Hcy was evidence of correction of a deficiency even when other laboratory or clinical measurements of a response were obscured.

Subacute combined degeneration of the spinal cord due to folate deficiency in association with a psychotic illness

Subacute combined degeneration of the cord which occurred as a result of dietary deficiency of folic acid in a patient with a psychotic illness, is described. A significant improvement in the neurological deficit occurred following treatment with folic acid. It is possible that treatment with folate also contributed to the improvement in the patient's psychiatric illness.

[Folic acid deficiency can cause severe anemia and pancytopenia]

Pancytopenia is occasionally a consequence of folate deficiency. The most important differential diagnostic considerations are haematologic malignancies, aplastic anaemia and vitamin B12 deficiency. We discuss the problem as exemplified by three patients. Bone marrow examination and determination of blood concentrations of vitamin B12 and folate will give the correct diagnosis.

Vitamin B-12 and folate deficiency presenting as leukaemia

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[Folate and vitamin B12 deficiency. Characterization of parameters for early diagnosis]

True vitamin B12/folate deficiency is more common than is currently appreciated; it appears in many guises and the classic hematological features of megaloblastic anaemia are often absent. The single most reliable predictor of megaloblastic anaemia is serum vitamin B12/folate concentration, but this determination in a screening program for all patients is difficult in terms of laboratory overload and cost. Early recognition of nutritional anaemias is, however, mandatory and we undertook this study to explore the possibility of identifying, on a demographic basis or because of routine laboratory results, a group of subjects at risk for vitamin B12/folate deficiency. Results obtained in simultaneous radioassay of serum B12 and folate levels and erythrocyte folate concentration in 1.200 hospitalized patients are presented. Coexisting iron deficiency was excluded by ferritin assay. We found no significant difference between males and females and no correlation between serum folate and B12 concentrations and aging. Low serum folic and cobalamin levels were found in 53% of patients with macrocytosis and elevated MCH, even in the absence of anaemia. These observations suggest that increased MCV and MCH may be present before a related anaemia and that serum folate and cobalamin levels must be monitored early in these patients to prevent a deficiency.

Diagnosing vitamin B12 deficiency, a common geriatric disorder

Vitamin B12 deficiency in the elderly is a common disorder associated with an increased morbidity if it goes undetected, as often happens. Its diagnosis can be enhanced if the clinician recognizes the associated clinical features of nonspecific symptoms, glossitis, and dermatologic and neuropsychiatric abnormalities, and realizes the limitations of various tests (serum B12 assay, parietal cell and intrinsic factor antibody, mean corpuscular volume, and Schilling tests). Available data indicate it is sufficient to prescribe replacement B12 injections three or four times a year.

The deoxyuridine suppression test performed on phytohaemagglutinin-stimulated peripheral blood cells fails to reflect in vivo vitamin B12 or folate deficiency

Because phytohaemagglutinin-stimulated lymphocytes acquire folate deficiency in vitro, we have re-examined the claim that the deoxyuridine suppression test (dU-test) based on such cells helps to diagnose megaloblastic states. dU-test results were obtained from the phytohaemagglutinin-stimulated blood cells of 77 patients at 6 concentrations of dU. 21 megaloblastic patients with cobalamin or folate deficiency did not have a mean blood dU-test result significantly higher than that of 21 normoblastic patients at any concentration of dU. Among all patients, however, there was a weak correlation between the blood and marrow dU-test results. Folic acid corrected the blood dU-test results more in the normoblastic than the megaloblastic patients, and a difference between the two groups appeared, but a large overlap persisted. Blood dU-test results tend to be higher in megaloblastic patients, but acquired folate deficiency obscures the distinction from normoblastic patients so that the test is not of diagnostic value.

Skin and mucosal manifestations in vitamin deficiency

The skin and mucosal changes in vitamin deficiency are described. Pellagra, which is the oldest known cutaneous manifestation among vitamin deficiencies, is reviewed. Cutaneous alterations caused by deficiency of the water-soluble vitamins B6, C, B1 and biotin, B12, folic acid, and riboflavin result in more mucosal alterations and are discussed. Alterations caused by fat-soluble vitamin deficiencies (vitamins A and K) are also considered.

Use of the deoxyuridine suppression test to evaluate vitamin B12 and folate status

The deoxyuridine suppression test (DUST), performed on bone marrow cells, or peripheral blood lymphocytes, provides a rapid, dynamic assessment of vitamin B12 and folate status. The principles of this test are described and the use of the DUST in haematological practice at Wellington Hospital is reviewed. The advantages of the test are the speed of obtaining results, and an accurate assessment of the patient's condition when other haematological tests may be misleading.

Folate deficiency presenting as pancytopenia in pregnancy

Folate deficiency is a well-known complication of pregnancy. We present a case of folate deficiency with profound pancytopenia. Although this is a well-known consequence of folate deficiency, we wish to reemphasize this dramatic complication of pregnancy.

Haematological abnormalities in oral lichen planus, candidiasis, leukoplakia and non-specific stomatitis

A series of 322 patients presenting with non-ulcerative conditions of the oral mucosa was examined for haematological abnormalities. The series was divided into 5 major groups--lichen planus (103 patients), candidiasis (50), leukoplakia (30), stomatitis or glossitis (66), and a miscellaneous group (73). The prevalence of anaemia, and deficiences in iron, folate and vitamin B12 in each group were compared with that found in 100 controls. The prevalence of anaemia in the series as a whole was not significantly increased, but the prevalences of sideropenia (14.0%), folate deficiency (4.7%) and vitamin B12 deficiency (3.1%) were increased as compared with controls. The prevalence of a haematological abnormality was increased in patients with lichen planus (18/103 p less than 0.05), stomatitis (15/66 p less than 0.01) and particularly in patients with Candidiasis (18/50 p less than 0.001). In the stomatitis group, approximately 45% of the male patients were found to have some haematological deficiency compared with less than 20% of the female patients. The increased prevalence of haematological deficiences suggests that patients presenting with non-ulcerative conditions of the oral mucosa (particularly candidiasis and non-specific stomatitis) should be screened haematologically and that, in some patients with candidiasis, haematological deficiencies may predispose towards candidal infection.

Masked vitamin B12 and folate deficiency in the elderly

1. A high incidence of vitamin B12 or folate deficiency, or both, may be found in the elderly, particularly those in hospital. This report concerns fifty cases detected in an inner-city-area geriatric unit during the course of routine clinical investigation. The majority had none of the classical haematological signs of vitamin B12 or folate deficiency, and all the patients reported had a mean corpuscular volume (MCV) of less than 100 fl. 2. There was a significant negative correlation between the MCV and the erythrocyte folate (P less than 0.01), supporting earlier published work using a low serum folate as an index of folate deficiency. 3. There was no correlation between the MCV and the serum vitamin B12. Published work differs on this point. 4. Serum iron, total Fe-binding capacity and percentage Fe saturation results were available in forty patients in this series. There was a significant positive correlation between the serum Fe and the MCV (P less than 0.01) and 34% of patients had haematological evidence of Fe deficiency. In the majority, however, there was no evidence that associated Fe deficiency had masked the haematological signs of vitamin B12 or folate deficiency. 5. More attention should be paid to the problem of 'masked' vitamin B12 and folate deficiency in the elderly. There is a case for routine screening of the elderly for vitamin B12 and folate deficiency irrespective of the MCV.