Forensic Biology Exam – Sample Collection, Body Fluid Identification & Presumptive/Confirmatory Testing|Verified Questions Provided with A+ Graded Rationales Latest Updated 2026

Forensic Biology Exam – Sample Collection, Body Fluid Identification & Presumptive/Confirmatory Testing|Verified Questions Provided with A+ Graded Rationales Latest Updated 2026 What 3 body fluids usually require presumptive testing? 1. blood 2. saliva 3. semen What types of DNA samples are collected for analysis in forensics? unknown samples, elimination samples, reference samples (suspects') Why should all liquid stains be dried prior to transport and storage? to prevent degradation What is ISO 18385? creates a "forensic grade" standard to minimize the risk of DNA contamination of products used to collect, store, and analyze biological material for forensic purposes What is a presumptive test? screens to indicate the presence of a body fluid What is a confirmatory test? verifies the presence of a specific compound/type of body fluid What body fluid(s) darken with an ALS? blood What body fluid(s) fluoresce with an ALS? semen and saliva What are 2 presumptive color tests for blood? 1. tetramethylbenzidine (TMB) 2. Kastle-Meyer (Phenolphthalein) What are 2 presumptive chemiluminescence/fluorescence tests for blood? 1. luminol 2. fluorescein What is the name of a well-used ALS in forensics? Polilight Why is the TMB presumptive blood test not used much? it is carcinogenic What molecule is the Kastle-Meyer reagent specific for? hemoglobin What are 2 disadvantages of luminol? 1. dark environment required for detection 2. reacts with household bleach Why should luminol and fluorescein be used as last resort tests? possible interference with DNA analysis and source of contamination (spray can run on vertical surfaces) ABAHemaTrace high sensitivity and specificity (human) for monoclonal antihuman hemoglobin antibody at 0.05 micro g/ml What are 2 disadvantages of ABAHemaTrace? 1. false negative from high dose hook effect 2. false positive to primates and ferrets Acid phosphatase (AP) test presumptive test for human semen Christmas tree stain (nuclear fast red) confirmatory semen test with microscopic identification of sperm cells within semen What part of the sperm cell is stained red with Nuclear Fast Red (Christmas Tree stain)? the head (DNA containing region) P30 Test confirmatory test for semen, tests for the presence of protein P30 (a prostate specific antigen) What body fluids may provide a false positive for a P30 test? male urine, male blood, breast milk, rectal secretions What is a presumptive test for saliva? SALIgAE test, amylase reacts to produ