Serology in COVID: Light the Lantern and Pave the Way to Unexplored .

International Guidelines have voted for PCR as the Gold Standard in COVID diagnosis. Nasoparyngeal swab is the preferred specimen for PCR. It has a high probability of diagnosing early infection. But the diagnostic sensitivity of nasopharyngeal PCR decreases with increase in lapse between the infection and presentation to hospital. This might lead to dire consequences of labelling these patients as false negative, though such patients have been proved to be potentially infective since viral shedding occurs through other body fluids (stools) for long. COVID infection reveals that the IgM antibodies start to appear as early as 5th day of infection and switches over to IgA within 2-3 days. The aim of the study was to see if COVID antibody testing be coupled with PCR for diagnosis especially in patients presenting late (more than 14 days) of onset of infection? And if the antibodies are giving values, hence can them be reported quantitatively rather than in qualitative fashion? The second objective was to see if the COVID antibody levels be used to monitor the disease severity? And if the antibody levels of SARS CoV 2 be used an indicator to monitor the recovery?

EP15A3 Based Precision and Trueness Verification of VITROS HbA1C Immunoassay.

Verification of analytical performance of measurands becomes an essential requirement for the laboratories before proceeding to patients' samples testing. In our study we have verified the performance of HbA1C Immunoturbidimetric assay (VITROS 5600) against manufacturers' claims using CLSI EP15A3 Guidelines. We performed our study using two concentrations of Quality Control from Bio-Rad (Level 1 and Level 2). A precision verification study was carried out using five replicates of QC per day for five days following which imprecision estimates in form of Within Run (Repeatability) %CV and Within Lab %CV were calculated and compared against manufacturer's claims. Second part of our study included derivation of grand mean from the results of 25 replicates of QC used for precision verification. This was compared against the Target Value of the assigned QC obtained from the peer group mean of laboratories participating in interlaboratory QC program (unityTM Interlab-Bio-Rad) for %bias estimation. The findings of our precision study showed an acceptable Within Lab imprecision (%CVWL-0.6%), while the %CV -repeatability (%CVR-0.54%) was greater than the manufacturer's claim (σR-0.5%). Hence upper verification limit for the manufacturer's claim (0.65%) was calculated against which the %CV Repeatability was compared and was found to be acceptable. The trueness verification showed that our grand mean (5.488%) was within the verification interval of the target value (5.462-5.497%) and hence the actual %bias was not statistically significant. Our study demonstrates that HbA1C immunoassay shows an acceptable performance consistent with the manufacturer's claims.

Cinderella in Serum Protein Electrophoresis.

Paraproteinemia is characterised by clonal proliferation of plasma cells. A common laboratory finding in paraproteinemia being a monoclonal peak in serum protein electrophoresis (M band). But there are factors which produce a peak similar to M spike in serum protein electrophoresis and these factors are known as pseudoparaproteins. This case report discusses a rare cause of pseudo M spike in a known case of autoimmune hemolytic anaemia due to administration of drug-Rituximab, a monoclonal antibody by itself.