Forensic Serology: Foundations and Core Vocabulary

An easy-level 30-question mock covering the foundational vocabulary, core concepts, and essential techniques of forensic serology for NFSU MSc and FACT candidates. All questions are at the definitional and conceptual level — covering blood identification, ABO grouping, semen identification, bloodstain pattern analysis basics, DNA fundamentals, and body fluid identification.

Topics include: definition and scope of forensic serology (blood group typing + body fluid ID + DNA + bloodstain analysis), ABO blood group system (antigens on red cells + antibodies in serum + genetic basis), Kastle-Meyer phenolphthalein test (presumptive blood test; haemoglobin peroxidase + H2O2 → pink), Rh factor (D antigen; Rh positive = D antigen present; forensic relevance), luminol test (haemoglobin iron + H2O2 → blue chemiluminescence; 1:10 million sensitivity), Teichmann crystal test (hemin crystals; haematin + NaCl + glacial acetic acid + heat = dark brown rhombic; confirmatory for blood), secretor status (80% secrete ABO antigens in body fluids; non-secretors test as O), Ouchterlony double diffusion (precipitin test; species identification of bloodstains), PSA p30 (prostate-specific antigen; confirmatory marker for semen; present without sperm), universal donor group O (no A or B antigens on red cells), acid phosphatase (presumptive test for semen; 400x higher in seminal plasma; not confirmatory), Hemastix TMB (tetramethylbenzidine; blue-green presumptive blood test; safer benzidine alternative), Takayama haemochromogen crystal test (haemochromogen crystals from pyridine + haematin; confirmatory for blood), ABO antigen location (A antigen = GalNAc on H antigen; B antigen = Gal on H antigen), TMB (tetramethylbenzidine; blue-green colour; oxidised by haemoglobin peroxidase), sperm microscopy (Christmas tree stain; nuclear fast red + picric acid; red heads + yellow tails), immunochromatographic PSA strip (RSID-Semen; ABAcard p30; rapid confirmatory for semen), hair shaft layers (cuticle + cortex + medulla; cuticle = overlapping scales; DNA in cortex nuclei), amylase for saliva identification (Phadebas test; SALIgAE; 40,000 U/mL in saliva), leucomalachite green LMG (malachite green leuco form → green colour; presumptive blood test), chain of custody (documented unbroken record from collection to court; break = admissibility challenge), passive bloodstains (gravity only; circular with crenation; satellite drops at higher fall height), precipitin test species identification (Ouchterlony double diffusion; anti-human serum + stain extract → precipitation line = human), mtDNA from hair (mitochondrial DNA from hair shaft; maternal lineage only; hundreds of copies per cell), presumptive vs confirmatory hierarchy (presumptive = screening; confirmatory = species or type specific; required for court), luminol and bleach (bleach = false positive by oxidising luminol; plant peroxidases also false positive), non-secretor impact on forensic ABO typing (non-secretor = no ABO antigens in body fluids; stain types as group O regardless of blood group), benzidine discontinuation (IARC Group 1 bladder carcinogen; replaced by KM and LMG), absorption-elution technique (ABO typing from stains; absorb antibody → wash → elute by heat → test on indicator red cells), and ELISA (enzyme-linked immunosorbent assay; quantitative immunological method for body fluid and protein identification).

Topics covered:

• Blood identification: KM, luminol, Teichmann, Takayama, TMB, LMG, HemaTrace
• ABO and Rh blood groups: antigen-antibody system, secretor status, universal donor
• Semen identification: AP, PSA/p30, Christmas tree stain
• Saliva identification: amylase, Phadebas
• Bloodstain pattern analysis: passive patterns, luminol applications
• DNA from biological evidence: hair mtDNA, secretor genetics
• Forensic procedures: chain of custody, precipitin species testing, absorption-elution

Allow 30 minutes.