Breastfed Infants With Spells, Tremor, or Irritability: Rule Out Vitamin B12 Deficiency.

BACKGROUND: In Norway, 5-10% of neonates and infants have biomarkers suggesting vitamin B12 deficiency from newborn screening tests and unselected clinical screening, respectively. AIMS: The aims were to identify risk factors and describe presenting symptoms and biochemical profiles in infants diagnosed with vitamin B12 deficiency. METHODS: In this case-control study, we searched hospital medical records for infants younger than one year born in 2011-2018, diagnosed with vitamin B12 deficiency. We compared 85 cases with a control group of 252 infants aged 3-7 months. Parents completed questionnaires. RESULTS: Of the 85 cases with vitamin B12 deficiency, 80% presented with spells (37%) of apneas, motor seizures, or absences within the first two months of life. Tremor (29%) and irritability (18%) were the most common findings at the first examination. Serum total homocysteine ≥10 µmol/L was found in 77% of cases compared to 28% of controls (P < 0.001). None of the mothers were vegetarians, but 25% reported a previous history of vitamin B12 deficiency and 7% had celiac disease. The dose of nitrous oxide given during labor was significantly associated with infant serum total homocysteine level at diagnosis (r = 0.37, 95% confidence interval = 0.16-0.55, P < 0.001) for cases, but not for controls. CONCLUSION: Spells, tremor, and irritability are common findings in early infant vitamin B12 deficiency. Nitrous oxide given during labor is proposed as a contributing risk factor to the development of early infant vitamin B12 deficiency.

The prevalence and clinical relevance of hyperhomocysteinemia suggesting vitamin B12 deficiency in presumed healthy infants.

BACKGROUND: Previous studies have demonstrated a high prevalence of biochemical vitamin B12 deficiency in infants in Norway. Increased total homocysteine (tHcy) is the most important marker of B12 deficiency in infants. There is a need to evaluate its clinical relevance. AIMS: To investigate the prevalence of hyperhomocysteinemia (S-tHcy > 8 µmol/L) suggestive of suboptimal B12 status and the prevalence of clinically relevant hyperhomocysteinemia in presumed healthy infants in Norway. Further, to evaluate risk factors, presence of symptoms and psychomotor development in these children. METHODS: In a prospective study we clinically examined 252 infants aged 3-7 months using standardized neurological and psychomotor tests prior to analyzing biochemical B12 deficiency markers in 250 infants. RESULTS: Twenty-five of 250 (10%) infants had hyperhomocysteinemia combined with clinically relevant symptoms suggestive of B12 deficiency. Hyperhomocysteinemia was associated with tremor, excessive sleep, and sub-normal scores in the fine motor section of the Ages and Stages Questionnaire. One-hundred and fourteen of 250 (46%) infants had hyperhomocysteinemia. Multiple regression analysis showed months of infant formula use as the strongest negative predictor for hyperhomocysteinemia. CONCLUSION: We have demonstrated associations between symptoms suggestive of infant B12 deficiency and increased levels of tHcy in presumed healthy infants The combination of hyperhomocysteinemia and associated relevant symptoms suggestive of B12 deficiency was a common finding, albeit most infants with hyperhomocysteinemia did not show symptoms.

Falsely markedly elevated 25-hydroxyvitamin D in patients with monoclonal gammopathies.

OBJECTIVES: Monoclonal immunoglobulins can cause interference in many laboratory analyses. During a 4 month period we observed seven patients with monoclonal disease and falsely extremely elevated 25-hydroxyvitamin D (25(OH)D) results above 160 ng/mL (>400 nmol/L) measured using an immunoassay from Abbott Diagnostics. Based on these findings, we studied the occurrence of falsely elevated 25(OH)D in samples with paraproteins and investigated possible mechanisms of the observed interference. METHODS: 25(OH)D was analyzed using the Architect i2000 platform from Abbott Diagnostics and a higher order method, liquid chromatography-mass spectrometry (LC-MS/MS), in serum samples from 50 patients with known monoclonal disease. Patients with falsely elevated 25(OH)D were included in further studies to elucidate the cause of interference. Spuriously elevated results were in addition analyzed on two alternative platforms (Siemens and Roche). RESULTS: Falsely elevated 25(OH)D levels were present in eight patients on the Abbott analyzer and one on the Siemens platform. Results from Roche were comparable with LC-MS/MS. Additional investigations excluded elevated concentrations of rheumatoid factor and heterophilic antibodies as the cause of interference in the Abbott assay. CONCLUSIONS: Laboratories should be aware of the risk of falsely elevated 25(OH)D in samples run on the Architect analyzer from patients with monoclonal disease. Highly elevated vitamin D results should be diluted and if the dilution is non-linear, rerun by a different method, preferably LC-MS/MS. In patients with spuriously elevated 25(OH)D without known monoclonal disease, the laboratory should consider requesting protein electrophoresis to exclude paraprotein interference.

Biological variation of holotranscobalamin and cobalamin in healthy individuals.

Data on biological variation for cobalamin and holotranscobalamin (holoTC) are limited. The aim of this study was to determine within-subject (CVI) and between-subject (CVG) biological variations for these analytes in a healthy population. We collected blood samples from 15 healthy volunteers (12 women and three men, 22-66 years) on the same weekday for 10 consecutive weeks. Serum samples were stored at -80 °C until analysis in duplicate in a single analytical run. The CVI and CVG were estimated by nested ANOVA. The CVI (95% CI) for cobalamin and holoTC was 6.7% (5.7-7.7) and 13.0% (11.5-15.0), respectively. The corresponding CVG was 24.1% (16.4-36.0) and 24.6% (16.3-37.7). The analytical variation (CVA) (95% CI) was 3.5% (3.2-4.0) for cobalamin and 2.4% (2.1-2.6) for holoTC. The index of individuality (II) was low (<0.6) for both cobalamin and holoTC and the reference change value (RCV) was 20.1% for cobalamin and 36.6% for holoTC. Our study describes the components of biological variation of cobalamin and holoTC in a healthy population, contributing to a better clinical interpretation of these biomarkers.

Intensive educational efforts combined with external quality assessment improve the preanalytical phase in general practitioner offices and nursing homes.

BACKGROUND: Errors in the preanalytical phase in clinical laboratories affect patient safety. The aim of this study was to evaluate the effect of intensive educational efforts together with external quality assessment (EQA) of the preanalytical phase from 2013 to 2015 to improve patient identification in primary health care in Norway. In addition, routines for venous and capillary blood sampling were investigated. METHODS: A preanalytical EQA was circulated in 2013 by the Norwegian Quality Improvement of Laboratory Examinations (Noklus) to general practitioner offices and nursing homes (n=2000) to obtain information about important issues to focus on before launching an intensive educational program with courses, posters and visits in 2013-2015. Preanalytical EQA surveys were further circulated in 2014 and 2015. RESULTS: The response rate varied between 42% and 55%. The percentages of participants asking for the patients' name and the Norwegian identification number increased from about 8% in 2013 to about 35% in 2015. The increase was similar for those participating in only one EQA survey and for those who participated in EQA surveys both in 2013 and 2015. Guidelines for venous and capillary blood sampling were not always followed. CONCLUSIONS: Educational efforts more than the preanalytical EQA influenced the actions and resulted in an increase in the percentages of participants that followed the guidelines for patient identification. Some aspects of blood sampling routines need improvement.

[Trends in the diagnosis and management of neonatal hyperbilirubinaemia]. / Endring i diagnostikk og behandling av hyperbilirubinemi hos nyfødte.

BACKGROUND: The guidelines for diagnosis and treatment of neonatal hyperbilirubinaemia were changed at Vestfold Hospital, Norway in 1994 and 2007. Universal screening for ABO-immunization was implemented in 2006. This article describes effects of these changes. MATERIAL AND METHODS: Blood-type immunization, phototherapy and exchange transfusions were prospectively recorded in the 21-year period 1988-2008. Three cohorts comprised the basis for the analyses: infants born in the time-periods 1988-93, 1994-2006 or 2007-2008. RESULTS: 6.2 % of the infants born 1988-93 and 6.7 % born 1994-2006 received phototherapy. Physiological hyperbilirubinaemia in term infants was the main reason for phototherapy in the first cohort, while it was hyperbilirubinemia in preterm infants in the second cohort. 4.8 % of the infants born 2007-8 received phototherapy. Exchange transfusion was performed in 0.02 % born 1994-2008 and 0.2 % born 1988-93. Such transfusions were undertaken more frequently in cases with RhD-immunization (7.8 %) than in those with ABO-immunization (2.0 %). Universal screening for ABO-immunization increased the percentage of diagnosed cases in the population from 2.1 % to 3.6 %. No case of kernicterus was diagnosed. INTERPRETATION: Fewer term infants were treated with phototherapy for hyperbilirubinaemia after the changes of therapeutic guidelines in 1994, while more preterm infants were treated after this change. Far less exchange transfusions are performed nowadays than before 1994. ABO-immunization has been diagnosed more often after implementation of universal screening.