• Muhammad Zain Arshad, Dawood Ahmad, Muhammad Hussain, Hamid Nawaz Tipu, Muhammad Omair Riaz, and Ayesha Tanveer.
• Department of Immunology, Armed Forces Institute of Pathology, Rawalpindi, Pakistan.
• J Coll Physicians Surg Pak. 2023 Mar 1; 33 (3): 292296292-296.

ObjectiveTo develop and validate in-house HEp-2 cell slides for the detection of ANA by indirect immunofluorescence.Study DesignCross sectional validation study. Place and Duration of the Study: Department of Immunology, Armed Forces Institute of Pathology Rawalpindi, Punjab, Pakistan, from April to September 2022.MethodologyThis study involved development of in-house HEp-2 cell slides after procuring cell lines, sub-culturing and fixing them on different slides using variety of fixatives under different protocols. After standardisation of procedure, validation of procedure was done by testing sera of 305 patients for ANA detection at 1:40 dilution on in-house HEp-2 cell slides and subsequently on commercial HEp-2 cell slides (gold standard). Indirect immunofluorescence was observed by the two observers working independently and kept blinded from the results interpreted by each other. Data were collected on a pre-designed proforma and then analysed. Sensitivity, specificity, and positive predictive value (PPV) and negative predictive values (NPV) of in-house HEp-2 cell slides were calculated.ResultSera of 305 patients were tested on in-house and commercial HEp-2 cell slides. Sensitivity and specificity of in-house HEp-2 cell slides for ANA detection were 96.92% and 99.58%, respectively. PPV and NPV of in-house HEp-2 cell slides came out to be 98.43% and 99.17% respectively.ConclusionIn-house HEp-2 cell slides are as effective as commercial HEp-2 cell slides for the detection of ANA and can be used as cost-effective alternative.Key WordsAntinuclear antibodies (ANA), Human epithelial type-2 (HEp-2), Immunofluorescence.

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