Singh, Ravinder

Abstract Background The lack of standardization and harmonization among ferritin assays results in significant variability in clinical values. These assays have different reference ranges and numerous clinical cut-offs for interpreting anemia and iron toxicity. This inconsistency is due to manufacturers using various calibrators. Such variability complicates the interpretation and comparison of results across different clinical settings. Methods Ferritin was ordered for 7815 patient samples in 3 months and assays were performed by DXI. Similarly, 5818 patients’ samples were run by Roche in two months. Both assays are FDA cleared and are commonly used by hundreds of clinical laboratories. Frequency of no of patients flagged low or flagged were calculated with respective reference ranges of Dxi and Cobas. Results 12 percent of the patients were flagged low by the Beckman assay and would have gotten both physician and patients attention. However, by the Roche assay only 4 percent were flagged low. This was alarming to our physicians and lab was told to investigate to find for this shift. Manufacturer/Time Range Total Volume Total High Total Low %High %Low Dxi-May-24 2617 368 326 14.1% 12% Dxi-Jun-24 2391 345 278 14% 12% Dxi-Jul-24 2807 500 308 17.8% 11% Cobas-801 August 2024 - Ferritin Go Live Cobas-801-Sep-24 2545 572 105 22% 4% Cobas-801-Oct-24 2841 695 121 24% 4% Conclusion Lack of Standardization and harmonization has serious consequences for the patients being tested for ferritin to diagnose deficiency of iron or high iron situations. We are planning to do a prospective study to determine clinical cut-offs by correlating Ferritin lab results with other gold standard biomarkers including bone marrow biopsy.

Abstract Background Vitamin D supplementation by human individuals has significantly increased in the world. In US the total stored 25-OH-Vitamin D3 and 25-OH-Vitamin D2 has significantly increased for both in summers and winters. Under sunlight exposure, 7 dehydrocholesterol is converted to Vitamin D3 and is endogenous source in mammals. However, most of the exogenous source for Vitamin D used to be Vitamin D2 which used to be extracted only from mushrooms but is now manufactured by supplement industry as well. In last decade most of the supplementation has been due to chemically synthesized Vitamin D3. Food is now supplemented by both D2 and D3. It is not clear what is the prevalence of D2 supplementation/consumption in American population. Competitive immunoassays do not consistently recover 25-OH-D2 compared to 25-OH-D3 and some antibodies used have variable or no cross reactivity with 25-OH-D2. LC-MS/MS method can easily distinguish the two and can help in providing the precise and accurate results for 25-OH-D2 and 25-OH-D3. Here we present what is the prevalence of Vitamin D2 consumption and toxicity in American population based on our LC-MS/MS methods. Methods The study measured vitamin 25-OH-D levels (total, D2, and D3) in 148,654 patients from Mayo Clinic as well as from other medical centers within the U.S. Patients age ranging from new-born babies to over 100 years, and represents Male, Female and Neutral genders. Samples were analyzed for 25-OH-Vitamin D by LC-MS/MS as published earlier. Unlike immunoassays, LC-MS/MS gave us separate results for 25-OH-D3 and 25-OH-D2 with 100 percent specificity. Results 25-OH-Vitamin D2 levels of greater than 10 was present in at least 10,358 and ranged from 10 to 205 ng/mL. Of 10,358, 51 percent had 20-50 ng/mL, 10 percent had 51-80 ng/mL, and 1.3 percent had >80 ng/mL, ranging from 81-205 ng/mL with a median of 92 ng/mL. Of the patients found at Total Vitamin D >80 ng/mL, toxic levels of both D2 and D3 were found more in females than males. There was no significant gender difference for Vitamin D3 consumption but for D2 consumption, mean and median levels were different in males and females. Conclusion Clinical lab testing should accurately measure both 25-OH-D3 and 25-OH-D2, otherwise the patient total Vitamin D values in circulation will be underestimated.

Cumulative mtDNA damage occurs in aging animals, and mtDNA mutations are reported to accelerate aging in mice. We determined whether aging results in increased DNA oxidative damage and reduced mtDNA abundance and mitochondrial function in skeletal muscle of human subjects. Studies performed in 146 healthy men and women aged 18–89 yr demonstrated that mtDNA and mRNA abundance and mitochondrial ATP production all declined with advancing age. Abundance of mtDNA was positively related to mitochondrial ATP production rate, which in turn, was closely associated with aerobic capacity and glucose tolerance. The content of several mitochondrial proteins was reduced in older muscles, whereas the level of the oxidative DNA lesion, 8-oxo-deoxyguanosine, was increased, supporting the oxidative damage theory of aging. These results demonstrate that age-related muscle mitochondrial dysfunction is related to reduced mtDNA and muscle functional changes that are common in the elderly.