Leone Lattes (1887–1954) was an Italian physician and researcher who developed early methods for investigating ABO blood group characteristics in dried stains. His work helped bridge the gap between Karl Landsteiner’s discovery of blood groups and the practical difficulties of examining blood recovered from clothing, surfaces and other crime-scene materials. The methods were important historical steps, but they had limitations that modern forensic students should understand.
The challenge after Landsteiner’s discovery
Landsteiner’s research in 1901 showed that human blood could be divided into immunologically different groups. With fresh blood, antigens on red blood cells and corresponding serum antibodies can be investigated through agglutination reactions. A forensic stain, however, is not a fresh blood sample. Drying, exposure and degradation can damage red blood cells, and the amount of usable material may be extremely small.
Forensic investigators therefore faced a specific question: could a blood group be inferred from a dried stain well enough to assist an investigation? The answer required a different procedure rather than simply applying fresh-blood grouping without modification.
What did Leone Lattes contribute?
Lattes focused on identifying blood-group antibodies, or isoagglutinins, that could sometimes remain recoverable from dried blood. His approach involved extracting material from the stain and observing reactions with known indicator red blood cells. Such reactions could, under suitable conditions, provide information about the blood group represented in the stain.
Historical dates need careful handling. A scholarly review of spot tests describes the Lattes crust test as developed in 1913, whereas National Institute of Justice training and several accounts emphasize Lattes’s 1915 work on standardizing the procedure. These dates describe stages in the development and publication of the technique rather than necessarily a single undisputed moment of invention.
Lattes subsequently reported practical medico-legal case experience. His investigations helped show that serology could potentially contribute to source assessment beyond the basic question of whether an item appeared to carry blood.
How the Lattes approach worked
The principle was immunological. Under the ABO system, serum antibodies may react with certain incompatible red blood cells, leading to agglutination. By exposing a recovered stain extract to appropriate indicator cells, an examiner could look for evidence
Evidence is any form of proof, such as objects, materials, or scientific findings, presented to establish or disprove a fact in a legal proceeding. It is used to reconstruct events and link or exclude individuals Read Full Definition of relevant antibody activity. The interpretation depended on the expected pattern of reactions and the adequacy of the control material.
Unlike modern DNA profiling
DNA profiling, also known as DNA fingerprinting, is a significant technique in forensic science that identifies individual's unique DNA patterns for various purposes such as establishing familial relationships or tracing genealogical roots. The technique, which Read Full Definition, this test did not read inherited sequences at multiple highly variable loci
A locus is the precise position of a gene on a chromosome. Different alleles of the same gene occupy the same locus. Read Full Definition. It sought group-related immunological features that many individuals shared. The technique also depended strongly on the survival and recovery of antibodies from a stain.
The limitations that mattered
The NIJ’s historical training material specifically identifies two important problems. First, very little active antibody might be recovered, producing weak or absent reactions and making the method unreliable in some samples. Second, some interpretations depended on the absence of reactions; a negative finding might reflect poor recovery rather than the inferred blood group. Later research on bloodstain grouping sought to overcome these weaknesses.
A further problem is that agglutination observations may be affected by extract concentration or nonspecific cell aggregation. Historical studies had to consider conditions under which false reactions or missed reactions might occur. These are not minor technical details; they determine whether a claimed group result is defensible.
Why an ABO agreement cannot identify a unique donor
Imagine that both a suspect and a stain were reported as blood group A. A shared ABO group would be compatible with the suspect’s blood, but it would also be compatible with blood from many other people. This is class-level information, not a unique identification. Conversely, an unequivocal incompatible group may support exclusion if the testing is appropriate and valid.
Forensic students should also separate blood identification, species attribution and donor comparison. Each addresses a different question. Lattes’s contribution involved historical serological grouping of stains; it did not make a visual stain diagnosis or automatically identify a named donor.
From the Lattes test to later bloodstain grouping
Through the twentieth century, forensic serology expanded to additional methods of detecting blood-group substances, including absorption-based procedures. These eventually offered more practical approaches for aged stains than the original early antibody extraction method. Later still, DNA
DNA, or Deoxyribonucleic Acid, is the genetic material found in cells, composed of a double helix structure. It serves as the genetic blueprint for all living organisms. Read Full Definition profiling transformed biological source comparison through genetic variation, while leaving the need for body-fluid identification and proper evidence interpretation intact.
Studying the Lattes test remains useful because it illustrates a recurring pattern in forensic science
Discover the fascinating field of Forensic Science, the application of scientific principles to legal matters. This post delves into its many disciplines, from DNA analysis to crime scene investigation, its importance in the justice system, Read Full Definition: a basic scientific discovery does not automatically become a reliable crime-scene test. A method must account for the sample matrix, recovery efficiency, specificityIn the context of laboratory equipment or analytical techniques, the term "specific" describes the capability of a machine or method to accurately and selectively detect particular molecules or substances while minimizing interference from others. Specificity Read Full Definition, sensitivityIn the context of laboratory equipment or analytical techniques, the term "sensitive" describes the capability of a machine or method to detect even very small amounts or concentrations of a substance. Sensitivity is a quantitative Read Full Definition and interpretive uncertainty.
What students should remember
- Landsteiner discovered foundational ABO blood group differences; Lattes worked on adapting this information to dried forensic stains.
- The early Lattes crust test relied on recoverable antibody activity, which could be weak or unstable.
- Historical accounts refer to both 1913 and 1915 because the technique was developed and then further studied and published.
- A blood-group match cannot prove that an individual is the unique source of a stain.
- Forensic methods must be assessed in the condition in which evidence is actually encountered, not only under ideal laboratory conditions.
Legacy
Leone Lattes belongs among the pioneers of forensic serology because he confronted a practical laboratory problem: how to obtain biologically meaningful information from material that had dried and deteriorated. His work was an early step toward systematic forensic bloodstain grouping. Its scientific importance is clearer, not weaker, when the limitations and subsequent improvements are described accurately.
Sources and further reading
- National Institute of Justice: ABO Groups — explanation of the Lattes approach and its limitations.
- Spot Tests: Past and Present — historical discussion of forensic ABO methods and the 1913 Lattes crust test.
- Nobel Prize: Karl Landsteiner — original ABO discovery background.
Read next: Karl Landsteiner and Forensic Serology and Forensic Serology.
