The identification of menstrual blood in forensic samples by logistic regression modeling of miRNA expression

Differentiation of five forensically relevant body fluids using a small set of microRNA markers

In forensic investigations, identifying the type of body fluid allows for the interpretation of biological evidence at the activity level. Over the past two decades, significant research efforts have focused on developing molecular methods for this purpose. MicroRNAs (miRNAs) hold great promise due to their tissue-specific expression, abundance, lack of splice variants, and relative stability. Although initial findings are promising, achieving consistent results across studies is still challenging, underscoring the necessity for both original and replication studies. To address this, we selected 18 miRNA candidates and tested them on 6 body fluids commonly encountered in forensic cases: peripheral blood, menstrual blood, saliva, semen, vaginal secretion, and skin. Using reverse transcription quantitative PCR analysis, we confirmed eight miRNA candidates (miR-144-3p, miR-451a, miR-205-5p, miR-214-3p, miR-888-5p, miR-891a-5p, miR-193b-3p, miR-1260b) with high tissue specificity and four (miR-203a-3p, miR-141-3p, miR-200b-3p, miR-4286) with lesser discrimination ability but still contributing to body fluid differentiation. Through principal component analysis and hierarchical clustering, the set of 12 miRNAs successfully distinguished all body fluids, including the challenging discrimination of blood from menstrual blood and saliva from vaginal secretion. In conclusion, our results provide additional data supporting the use of a small set of miRNAs for predicting common body fluids in forensic contexts. Large population data need to be gathered to develop a body fluid prediction model and assess its accuracy.

Screening and evaluation of endogenous reference genes for miRNA expression analysis in forensic body fluid samples

MicroRNA (miRNA)-based methods for body fluid identification are promising tools in the practice of forensic science. The selection of appropriate endogenous reference genes as normalizers for the relative quantification of miRNA expression levels using quantitative reverse transcription-polymerase chain reaction (RTqPCR) is essential to avoid errors and improve the comparability of miRNA expression level data among different body fluids. In this study, small RNAs were isolated from individual donations of five forensically relevant body fluids (peripheral blood, menstrual blood, saliva, semen and vaginal secretions). Thirty-seven samples were subjected to high-throughput miRNA sequencing. By combining our results with those obtained through a literature investigation, 28 candidate RNAs were identified. Following RTqPCR validation, the candidate RNAs were preliminarily evaluated in 15 samples to exclude miRNAs with low expression and high variation. Then, the expression levels of 10 relatively stable candidate reference RNAs in 100 samples were determined and further analysed using four commonly employed programs (geNorm, NormFinder, BestKeeper and ΔCq). According to the comprehensive stability rankings of the four algorithms, miR-320a-3p was validated as the most stable endogenous reference gene among the five forensically relevant body fluids, followed by miR-484, SNORD43, miR-320c and RNU6b. Moreover, the combined application of miR-320a-3p with RNU6b could increase the normalization effect. In addition, a total of 56 mock samples placed outdoors and indoors for different times were prepared to further evaluate the stability of candidate reference RNAs, and miR-320a-3p remained the preferred reference gene. Furthermore, the relative expression levels of publicly accepted body fluid-specific miRNAs were determined in 30 samples to verify the practicality and effectiveness of the reference genes. Our results revealed a set of alternative reference genes and could promote the development and application of miRNA-based body fluid identification by determining optional reference genes for strict normalization.

Review of the current and potential use of biological and molecular methods for the estimation of the postmortem interval in animals and humans

We provide here an overview of the state of applied techniques in the estimation of the early period of the postmortem interval (PMI). The biological methods included consist of body cooling, CSF potassium, body cooling combined with CSF potassium, and tissue autolysis. For each method, we present its application in human and veterinary medicine and provide current methodology, strengths, and weaknesses, as well as target areas for improvement. We examine current and future molecular methods as they pertain to DNA and primarily to messenger RNA degradation for the estimation of the PMI, as well as the use of RNA in aging wounds, aging blood stains, and the identification of body fluids. Various types of RNA have different lengths, structures, and functions in cells. These differences in RNAs determine various intrinsic properties, such as their half-lives in cells, and, hence, their decay rate as well as their unique use for specific forensic tests. Future applications and refinements of RNA-based techniques provide opportunities for the use of molecular methods in the estimation of PMI and other general forensic applications.

A new strategy for distinguishing menstrual blood from peripheral blood by the miR-451a/miR-21-5p ratio

Distinction between menstrual blood and peripheral blood is vital for forensic casework, as it could provide strong evidence to figure out the nature of some criminal cases. However, to date no single blood-specific gene, including the most variable microRNAs (miRNAs) could work well in identification of blood source. In this study, we developed a new strategy for identification of human blood samples by using the copy number ratios of miR-451a to miR-21-5p based on 133 samples, including 56 menstrual blood and 47 peripheral blood, as well as 30 non-blood samples of saliva (10), semen (10) and vaginal secretion (10). The cut-off value and efficacy of the identification strategy were determined through receiver operating characteristic (ROC) analysis. Our results showed that when the miR-451a/miR-21-5p ratio below 0.929, the sample should be non-blood. In contrast, when the miR-451a/miR-21-5p ratio above 0.929 and below 10.201, the sample should be menstrual blood; and when this ratio above 10.201, the sample should be peripheral blood. External validation using 86 samples (62 menstrual blood and 24 peripheral blood samples) fully supported this strategy with the 100% sensitivity and 100% specificity. We confirmed that this result accuracy was not affected by various potential confounding factors of samples and different experimental platforms. We showed that 0.2 ng of total RNA from menstrual blood and peripheral blood was sufficient for qPCR quantification. In conclusion, our results provide an accurate reference to distinguish menstrual blood from peripheral blood for forensic authentication.

Magnetic ionic liquids as microRNA extraction solvents and additives for the exponential amplification reaction

The detection of microRNAs (miRNAs) from highly complex matrices has become an area of immense interest as their characterization in biological samples has been utilized for disease diagnosis and body fluid identification. However, conventional northern blotting miRNA detection lacks the sensitivity required to detect circulating miRNAs. Additionally, polymerase chain reaction-based methods for miRNA detection require modified oligonucleotides that are difficult to design. Exponential amplification reaction (EXPAR) is an isothermal amplification method used for miRNA detection that is simple to design but suffers from non-specific amplification that masks low concentration miRNAs. Previous studies have shown that magnetic ionic liquids (MILs) are a promising alternative to traditional nucleic acid extraction methods capable of preconcentrating DNA from complex matrices. In this study, three hydrophobic magnetic ionic liquids (MILs) were investigated as EXPAR additives and miRNA extraction solvents. The addition of MIL to the EXPAR buffer decreased the background signal from non-specific amplification and increased the reaction rate. Reactions containing MIL could detect miRNA at concentration levels down to 10 aM. In comparison, reactions that did not contain MIL could not discriminate 10 fM lethal-7a (let-7a) standards from the no trigger control (NTC). All three MILs extracted miRNA from 2-fold diluted plasma, artificial urine, and artificial saliva with only a 1 min dispersion step. By integrating the miRNA-enriched MIL into the EXPAR buffer, the extraction and detection of femtomolar concentrations of miRNA required only 10 min. In contrast, conventional spin column kits require at least 20 min to isolate miRNA, indicating that a dispersive MIL-based extraction is ideal for high throughput analysis of miRNA.

Detection of bloodstains using attenuated total reflectance-Fourier transform infrared spectroscopy supported with PCA and PCA-LDA

The most important task in a criminal investigation is to detect and identify the recovered biological stains beyond reasonable scientific doubt and preserve the sample for further DNA analysis. In the light of this fact, many presumptive and confirmatory tests are routinely employed in the forensic laboratories to determine the type of body fluid. However, the currently used techniques are specific to one type of body fluid and hence it cannot be utilized to differentiate multiple body fluids. Moreover, these tests consume the samples in due process, and thus it becomes a great limitation especially considering the fact that samples are recovered in minute quantity in forensic cases. Therefore, such limitations necessitate the use of non-destructive techniques that can be applied simultaneously to all types of bodily fluids and allow sample preservation for further analysis. In the current work, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy has been used to circumvent the aforementioned limitations. The important factors which could influence the detection of blood such as the effect of substrates, washing/chemical treatment, ageing, and dilution limits on the analysis of blood have been analysed. In addition, blood discrimination from non-blood substance (biological and non-biological in nature) has also been studied. Chemometric technique that is PCA-LDA has been used to discriminate blood from other body fluids and it resulted in 100% accurate classification. Furthermore, blood and non-blood substances including fake blood have also been classified into separate clusters with a 100% accuracy, sensitivity, and specificity. All-inclusive, this preliminary study substantiates the potential application of ATR-FTIR spectroscopy for the non-destructive identification of blood traces in simulated forensic casework conditions with 0% rate of false classification.

Surface enhanced Raman scattering specificity for detection and identification of dried bloodstains

Surface enhanced Raman spectroscopy (SERS) provides highly specific vibrational signatures identifying dried blood for a variety of forensic applications. SERS spectra on Au nanoparticle substrates excited at 785 nm are found to identify dried stains of human and nonhuman blood from seven animals, and distinguish stains due to menstrual and peripheral blood. In addition, the unique SERS bloodstain spectrum is distinct from the SERS spectra of thirty red-brown stains of potential household substances that could be visually mistaken for bloodstains and from food stains that have been shown to give positive results with presumptive colorimetric blood tests. Finally, a SERS swab procedure has been developed and demonstrates that the substrates that a blood sample dried on does not offer any Raman or fluorescence interference for the SERS identification of dried blood. Such bloodstains on porous and nonporous materials are all identical and exclusively due to the heme moiety of hemoglobin. Optimized selection of the extraction solvent is found to control the chemical composition of molecular components appearing in the SERS spectrum of complex, multicomponent biological mixtures, such as body fluids.

Discrimination of menstrual and peripheral blood traces using attenuated total reflection Fourier transform-infrared (ATR FT-IR) spectroscopy and chemometrics for forensic purposes

Body fluid traces can provide highly valuable clues in forensic investigations. In particular, bloodstains are a common occurrence in criminal investigation, and the discrimination of menstrual and peripheral blood is a crucial step for casework involving rape and sexual assault. Most of the current protocols require the detection of characteristic menstrual blood components using sophisticated procedures that need to be performed in a laboratory. The present study uses attenuated total reflection Fourier transform-infrared (ATR FT-IR) spectroscopy as a nondestructive technique for discriminating menstrual and peripheral blood traces. This method incorporates statistical analysis and was evaluated by internal and external validation testing. A partial least squares discriminant analysis (PLSDA) classification model was created for differentiating the two types of blood in a binary manner. Excellent separation between menstrual and peripheral blood samples was achieved during internal validation. External validation resulted in 100% accuracy for predicting a sample as peripheral or menstrual blood. This study demonstrates that ATR FT-IR spectroscopy combined with chemometrics is a reliable approach for rapid and nondestructive discrimination of menstrual and peripheral bloodstains. It offers a significant advantage to forensic science due to the availability of portable instruments and the potential for bloodstain analysis at a crime scene. Graphical abstract.

A systematic analysis of miRNA markers and classification algorithms for forensic body fluid identification

Identifying the types of body fluids left at the crime scene can be essential to reconstructing the crime scene and inferring criminal behavior. MicroRNA (miRNA) molecule extracted from the trace of body fluids is one of the most promising biomarkers for the identification due to its high expression, extreme stability and tissue specificity. However, the detection of miRNA markers is not the answer to a yes-no question but the probability of an assumption. Therefore, it is a crucial task to develop complicated methods combining multi-miRNAs as well as computational algorithms to achieve the goal. In this study, we systematically analyzed the expression of 10 most probable body fluid-specific miRNA markers (miR-451a, miR-205-5p, miR-203a-3p, miR-214-3p, miR-144-3p, miR-144-5p, miR-654-5p, miR-888-5p, miR-891a-5p and miR-124-3p) in 605 body fluids-related samples, including peripheral blood, menstrual blood, saliva, semen and vaginal secretion. We introduced the kernel density estimation (KDE) method and six well-established methods to classify the body fluids in order to find the most optimal combinations of miRNA markers as well as the corresponding classifying method. The results show that the combination of miR-451a, miR-891a-5p, miR-144-5p and miR-203a-3p together with KDE can achieve the most accurate and robust performance according to the cross-validation, independent tests and random perturbation tests. This systematic analysis suggests a reference scheme for the identification of body fluids in an accurate and stable manner.

Expression profile analysis and stability evaluation of 18 small RNAs in the Chinese Han population

In recent years, differentially expressed small RNAs have been widely used to identify the compositions of forensically relevant biological samples, and a vast number of such RNA candidates have been proposed. Nevertheless, when assessing the expression levels of target small RNAs using relative quantitative analysis methods, credible internal controls are usually required for reliable data normalization. Therefore, the identification of optimal reference genes is an important task. In this study, the expression profile of 18 small RNA reference genes was characterized in the Chinese Han population using TaqMan real-time quantitative PCR. Systematic evaluations of these candidate genes were performed based on their expression levels and stability in several common types of body fluids (i.e., venous blood, menstrual blood, saliva, semen, and vaginal secretions). Analysis results from the ΔCq method, BestKeeper, NormFinder, and geNorm were integrated by RefFinder for ranking and comparing the candidates in each type of body fluid. Among all the candidates, miR-191 was identified as the most suitable reference gene because it had a favorable ranking value in all tested samples. In addition, miR-423, miR-93, miR-484, and let-7i were also shown to be applicable reference genes. Overall, this study provides detailed assessment results of these candidate genes in different body fluids; thus, it could be used as a guide for the selection of reference genes according to their performance in the sample of choice.

Identification of five types of forensic body fluids based on stepwise discriminant analysis

Peripheral blood, menstrual blood, semen, saliva and vaginal secretions are the five most common body fluids found at crime scenes, and the identification of these five body fluids is of great significance to the reconstruction of a crime scene and resolution of the case. However, accurate identification of these five body fluids is still a challenge. To address this problem, a mathematical model for differentiating five types of forensic body fluids based on the differential expression characteristics of multiple miRNAs in five body fluids (peripheral blood, menstrual blood, semen, saliva and vaginal secretions) was developed. A total of 350 forensic body fluids (70 of each type) were collected and tested, and relative expression of 10 miRNAs (miR-451a, miR-205-5p, miR-203-3p, miR-214-3p, miR-144-3p, miR-144-5p, miR-654-5p, miR-888-5p, miR-891a-5p, miR-124a-3p) in all samples was detected by SYBR Green real-time qPCR. Three hundred samples (60 samples of each body fluid) were used as the training set to screen meaningful identification markers by stepwise discriminant analysis, and a discriminant function was established. Fifty samples (10 samples of each body fluid) were used as a validation set to examine the accuracy of the model, and 25 samples (the types of samples were unknown to the experimenter) were used for a blind test. Except for miR-144-3p, the other miRNAs were selected to construct discriminant analysis models. The self-validation accuracy of the model was 99.7 %, cross-validation accuracy was 99.3 %, accuracy of the identification validation set was 100 %, and accuracy of the blind test result was 100 %. This study provides a reliable and accurate identification strategy for five common body fluids (peripheral blood, menstrual blood, semen, saliva, and vaginal secretions) in forensic medicine.

Potential applications of microRNA profiling to forensic investigations

Within the forensic science community, there is a continued push to develop novel tools to aid in criminal investigations. microRNA (miRNA) analysis has been the focus of many researcher's attention in the biomedical field since its discovery in 1993; however, the forensic application of miRNA analysis has only been suggested within the last 10 years and has been gaining considerable traction recently. The primary focus of the forensic application of miRNA analysis has been on body fluid identification to provide confirmatory universal analysis of unknown biological stains obtained from crime scenes or evidence items. There are, however, other forensic applications of miRNA profiling that have shown potential, yet are largely understudied, and warrant further investigation such as organ tissue identification, donor age estimation, and more. This review paper aims to evaluate the current literature and future potential of miRNA analysis within the forensic science field.

A stepwise strategy to distinguish menstrual blood from peripheral blood by Fisher's discriminant function

Blood samples are the most common and important biological samples found at crime scenes, and distinguishing peripheral blood and menstrual blood samples is crucial for solving criminal cases. MicroRNAs (miRNAs) are important molecules with strong tissue specificity that can be used in forensic fields to identify the tissue properties of body fluid samples. In this study, the relative expression levels of four different miRNAs (miR-451, miR-205, miR-214 and miR-203) were analysed by real-time PCR, with 200 samples from 5 different body fluids, including two kinds of blood samples (peripheral blood and menstrual blood) and three kinds of non-blood samples (saliva, semen and vaginal secretion). Then, a strategy for identifying menstrual and peripheral blood based on Fisher's discriminant function and the relative expression of multiple miRNAs was established. Two sets of functions were used: Z1 and Z2 were used to distinguish blood samples from non-blood samples, and Y1 and Y2 were used to distinguish peripheral blood from menstrual blood. A 100% accuracy rate was achieved when 50 test samples were used. Ten samples were used to test the sensitivity of the method, and 10 ng or more of total RNA from peripheral blood samples and 10 pg or more of total RNA from menstrual blood samples were sufficient for this method. The results provide a scientific reference to address the difficult forensic problem of distinguishing menstrual blood from peripheral blood.

Distinct spectrum of microRNA expression in forensically relevant body fluids and probabilistic discriminant approach

MicroRNA is attracting worldwide attention as a new marker for the identification of forensically relevant body fluids. A probabilistic discriminant model was constructed to identify venous blood, saliva, semen, and vaginal secretion, based on microRNA expression assessed via RT-qPCR. We quantified 15 candidate microRNAs in four types of body fluids by RT-qPCR and found that miR-144-3p, miR-451a-5p, miR-888-5p, miR-891a-5p, miR-203a-3p, miR-223-3p and miR-1260b were helpful to discriminate body fluids. Using the relative expression of seven candidate microRNAs in each body fluid, we implemented a partial least squares-discriminant analysis (PLS-DA) as a probabilistic discriminant model and distinguished four types of body fluids. Of 14 testing samples, 13 samples were correctly identified with >90% posterior probability. We also investigated the effects of microRNA expression in skin, semen infertility, and vaginal secretion during different menstrual phases. Semen infertility and menstrual phases did not affect our body fluid identification system. Therefore, the selected microRNAs were effective in identifying the four types of body fluids, indicating that probabilistic evaluation may be practical in forensic casework.

Forensic discrimination of menstrual blood and peripheral blood using attenuated total reflectance (ATR)-Fourier transform infrared (FT-IR) spectroscopy and chemometrics

Body fluids are one of the most important pieces of evidence encountered in forensic cases especially in cases of sexual assault. Analysis of such evidence can help to establish a link between the perpetrator, the victim, and the crime scene and thereby assist in crime reconstruction. However, one of the biggest challenges faced by the investigators in sexual assault cases is that of ascertaining the issue of consent of the victim. In this matter, differentiation of menstrual blood (either in dried or stained form) from traumatic peripheral blood can give a potential solution on this particular aspect. A number of studies have been attempted to differentiate these two body fluids using various biochemical and serological methods. However, the methods employed are limited by factors such as sample destructivity and non-specificity, and the methods are susceptible to false positive results. In the present study, the scope of attenuated total reflectance (ATR)-Fourier transform infrared (FT-IR) spectroscopy in discriminating samples of menstrual blood and peripheral blood has been investigated, in combination with chemometric tools such as principal component analysis (PCA), partial least square regression (PLSR), and linear discriminant analysis (LDA). PCA resulted in 93.3% accuracy, whereas PLSR and LDA resulted in 100% accuracy for the discrimination of peripheral blood from menstrual blood. Application of PCA for the discrimination of menstrual blood from vaginal fluid and seminal fluid delivered 100% classification. Similarly, 100% classification was achieved while differentiating between menstrual blood and blood look-alike substances. Furthermore, in the current study, the effect of substrates on the analysis of menstrual blood has also been studied and described. Graphical Abstract.

The expression of 10 candidate specific microRNA markers for human body fluid identification in animal buccal swabs

MicroRNAs (miRNAs) have been of interest in forensic science for body fluid identification with recent years. However, there is no study investigating the species specificity of miRNA markers by the SYBR Green method. Due to the conservation of miRNAs across species, miRNA markers maybe less species-specific than mRNA markers, and in forensic cases, animal buccal swabs are more likely to appear. Therefore, in this study we addressed the influence of 8 kinds of animal buccal swabs on human saliva, semen, vaginal secretion swabs and blood identification with 10 candidate specific miRNA markers by the SYBR Green quantitative PCR. Our data showed that the expression levels of the candidate specific miRNA markers miR-124a and 372 in the cat, dog, mouse and rabbit buccal swabs were in the same range as the human vaginal secretion swabs; buccal swabs from these animals also showed similar expression levels to human saliva for the candidate specific miRNA markers miR-200c, 205 and 658. These results indicated that biomaterials of buccal swabs from cats, dogs, mice and rabbits may be mistaken for human saliva or human vaginal secretion swabs, both of which could result in false positives for human body fluids. Thus, the interpretation of these miRNA profiles for human body fluid identification can be inaccurate in the presence of these animal buccal swabs. Therefore, we suggested performing species tests before human body identification with miRNA markers.

Human Organ Tissue Identification by Targeted RNA Deep Sequencing to Aid the Investigation of Traumatic Injury

Molecular analysis of the RNA transcriptome from a putative tissue fragment should permit the assignment of its source to a specific organ, since each will exhibit a unique pattern of gene expression. Determination of the organ source of tissues from crime scenes may aid in shootings and other investigations. We have developed a prototype massively parallel sequencing (MPS) mRNA profiling assay for organ tissue identification that is designed to definitively identify 10 organ/tissue types using a targeted panel of 46 mRNA biomarkers. The identifiable organs and tissues include brain, lung, liver, heart, kidney, intestine, stomach, skeletal muscle, adipose, and trachea. The biomarkers were chosen after iterative specificity testing of numerous candidate genes in various tissue types. The assay is very specific, with little cross-reactivity with non-targeted tissue, and can detect RNA mixtures from different tissues. We also demonstrate the ability of the assay to successful identify the tissue source of origin using a single blind study.

Forensic differentiation between peripheral and menstrual blood in cases of alleged sexual assault-validating an immunochromatographic multiplex assay for simultaneous detection of human hemoglobin and D-dimer

Sexual assault is a serious offense and identification of body fluids originating from sexual activity has been a crucial aspect of forensic investigations for a long time. While reliable tests for the detection of semen and saliva have been successfully implemented into forensic laboratories, the detection of other body fluids, such as vaginal or menstrual fluid, is more challenging. Especially, the discrimination between peripheral and menstrual blood can be highly relevant for police investigations because it provides potential evidence regarding the issue of consent. We report the forensic validation of an immunochromatographic test that allows for such discrimination in forensic stains, the SERATEC PMB test, and its performance on real casework samples. The PMB test is a duplex test combining human hemoglobin and D-dimer detection and was developed for the identification of blood and menstrual fluid, both at the crime scene and in the laboratory. The results of this study showed that the duplex D-dimer/hemoglobin assay reliably detects the presence of human hemoglobin and identifies samples containing menstrual fluid by detecting the presence of D-dimers. The method distinguished between menstrual and peripheral blood in a swab from a historical artifact and in real casework samples of alleged sexual assaults. Results show that the development of the new duplex test is a substantial progress towards analyzing and interpreting evidence from sexual assault cases.

Evaluating the forensic application of 19 target microRNAs as biomarkers in body fluid and tissue identification

RNA-based body fluid and tissue identification has evolved as a promising and reliable new technique to classify type and source of biological evidence in crime cases. In particular, mRNA-based approaches are currently on the rise to replace conventional protein-based methods and are increasingly implemented into forensic casework. However, degradation of these nucleic acid molecules can cause issues on laboratory scale and need to be considered for a credible investigation. For this reason, the analysis of miRNAs using qPCR has been proposed to be a sensitive and specific approach to identify the origin of a biological trace taking advantage of their small size and resistance to degradation. Despite the straightforward workflow of this method, suitable endogenous controls are inevitable when performing real-time PCR to ensure accurate normalization of gene expression data in order to allow a meaningful interpretation. In this regard, we have validated reference genes for a set of forensically relevant body fluids and tissues (blood, saliva, semen, vaginal secretions, menstrual blood and skin) and tested 15 target genes aiming to identify abovementioned sample types. Our data showed that preselected endogenous controls (miR26b, miR92 and miR484) and miR144, initially selected as potential marker for the detection of menstrual blood, were the most stable expressed genes among our set of samples. Normalizing qPCR data with these four validated references revealed that only five miRNA markers are necessary to differentiate between the six different cell types selected in this study. Nevertheless, our observations in the present study indicate that miRNA analysis methods may not provide straightforward data interpretation strategies required for an implementation in forensic casework.

Validation of an immunochromatographic D-dimer test to presumptively identify menstrual fluid in forensic exhibits

Identifying the biological source of a crime scene stain can be crucial for police investigations in many scenarios. Blood is one of the most common fluids found, and accurate differentiation between peripheral blood and menstrual fluid could provide valuable information regarding the issue of consent in sexual assault cases. For the detection of menstrual fluid, no easy-to-use presumptive test is available to date. Therefore, this study aimed to validate a simple immunochromatographic test for the indication of menstrual fluid, focusing on a D-dimer assay. The Clearview® rapid D-dimer test provides a diagnostic assay for the detection of fibrin degradation products. We validated the sensitivity and robustness of the assay using fresh and dried menstrual fluid samples, body fluid mixtures, diluted samples, and casework swabs. Cross reactivity was tested for saliva, semen, vaginal fluid, and blood. No false positive results were obtained; it was possible to successfully analyze mixtures, highly diluted samples, and casework swabs. The results of this study indicate that the D-dimer assay reliably detects menstrual fluid in forensic exhibits and is easy to implement into the current workflow of body fluid identification.