623.1Blood and Other Bodily Fluids

Law and Issues
Last Updated: 12/01/23

Key Concepts

  • Expert testimony about the results of testing for the presence of blood and other bodily fluids is generally admissible at trial, upon laying a proper foundation.
  • Testimony about the likelihood that the blood sample is a “match” to the defendant or any other person may be admissible, depending upon the degree of certainty (and the corresponding probative value) of the possible match.

Admissibility and Reliability 

Expert testimony about test results for the presence and characteristics of blood, semen, saliva, and other bodily fluids has generally been held reliable and admissible in North Carolina, upon laying a proper foundation. See, e.g., State v. Dennis, 129 N.C. App. 686 (1998) (court ruled that expert testimony about the results of a test using “Phadebas Methodology,” which indicated the presence of saliva on vaginal swabs, was properly admitted; evidence presented at trial showed that the test possessed sufficient indices of reliability); State v. Gray, 292 N.C. 270 (1977) (blood absorption inhibition tests were properly admitted in rape prosecution).  

Due to the development of more modern and precise methods of DNA analysis, the type of testing at issue in older cases is now used mainly as a tool to identify samples for further analysis, rather than as an independent basis for rendering a final opinion. (For more information, see the related expert testimony entry on DNA Evidence, or contact the NC State Crime Lab Forensic Biology and DNA Section.) As a result, there are not yet any North Carolina appellate cases directly addressing the admissibility of expert testimony on such testing, standing alone, under the post-2011 amended version of Rule 702 adopting the Daubert standard. However, at least one North Carolina appellate case has considered the admissibility of expert testimony on a related issue under Daubert, and found that it was not prejudicial error to admit the testimony. See State v. Mack, 252 N.C. App. 93 (2017) (unpublished) (applying Daubert factors and finding “the trial court did not commit reversible error in allowing Levins' opinion testimony,” and concluding that there was no prejudice where trial court permitted state’s “expert witness in forensic serology to offer an opinion as to the manner in which semen stains were made on a hand towel”). 

Federal courts applying the Daubert standard have both admitted and excluded testimony about testing for the presence of bodily fluids, depending on the scope of the proposed opinion and whether the proponent of the evidence has met the threshold for satisfying each prong of the reliability test. Compare U.S. v. Hill, 41 M.J. 596 (Army Ct. Crim. App. 2015) (“the government, as the party offering the expert testimony, failed to meet the Daubert reliability standard for the admission of expert testimony” about luminol testing for presence of blood, because “the evidence indicated that luminol is reliable only to show a presumptive positive presence for blood and not to confirm the presence of blood”) with U.S. v. Holt, 46 M.J. 853 (Navy-Marine Ct. Crim. App. 1997) (“Luminol testing is simply not a new or novel scientific evidentiary process, and has been accepted by the single military appellate court to consider it—even under a post-Daubert analysis.”); see also U.S. v. Frazier, 387 F.3d 1244 (11th Cir. 2004) (applying Daubert, trial court did not abuse its discretion by both allowing and excluding different portions of expert testimony regarding presence or absence of semen in a kidnapping and sexual assault case). 

Any weaknesses in the chain of custody affect the weight of the evidence, not its admissibility. See State v. Grier, 307 N.C. 628 (1983)State v. Fulton, 299 N.C. 491 (1980) (chain of custody of defendant’s tennis shoes, after they were received in the mail by an SBI agent, was not so broken to require the exclusion of tests performed on bloodstains because the agent may have left the shoes unattended for an hour in his unlocked, private office or because, after they had been examined, the shoes were carried to a mail pickup point by person other than the agent).  

Scope of Opinion 

Assuming the opinion testimony is admissible, and upon showing a proper foundation and basis for the opinion, the witness may testify as to both the nature of the substance (e.g., blood, saliva, or semen) and the likelihood that the substance did or did not come from the defendant. See State v. Payne, 328 N.C. 377 (1991) (opinion of SBI agent that only one percent of North Carolinians had same blood characteristics as victim was admissible; estimate of SBI agent about how many blood analyses he had performed in his career was admissible); but see State v. Fulton, 299 N.C. 491 (1980) (testimony by an expert in forensic serology that human blood found on defendant’s tennis shoes was consistent with the victim’s blood grouping and that this blood type was present in only 11% of the population was “relevant but weakly probative,” making it “mildly unfavorable to defendant but essentially harmless because its probative value is so minute. Certainly no prejudice resulted.”); see also State v. Acklin, 317 N.C. 677 (1986) (laboratory reports prepared by two forensic SBI chemists that showed that pubic hair and semen found on victim were not attributable to defendant were admissible against the state in rape and kidnapping prosecution as a report of a public agency). 

Practice Pointer

Other options? 
Prosecutors should exercise caution in this area, and make sure the expert’s opinion at trial is limited to what the testing and evidence can support. See, e.g., State v. Taylor, 91-CRS-71728 (Wake County, 2010) (defendant exonerated for actual innocence, pursuant to Article 92 of Chapter 15A, based in part on the fact that improper evidence was presented to the jury through a lab report regarding tests performed on several droplets recovered from defendant’s vehicle that showed “preliminary indications” for blood, even though undisclosed confirmatory testing revealed that the droplets were not actually blood); see also State v. Taylor, 91-CRS-71728, Transcript of North Carolina Innocence Commission Inquiry, p. 114-133 (Wake County, 2009). 
In most cases where the state has recovered a sample of blood or other bodily fluids, modern DNA testing will yield much more precise results and should be utilized whenever possible. But if that type of testing is not available for some reason (e.g., limited lab resources or the nature of the sample), then the alternative tests described in this entry should still be admissible, as long as the results are sufficiently probative and reliable.