Preference of saliva over other body fluids as samples for clinical and laboratory investigations among healthcare workers in Ibadan, Nigeria

Introduction The study aimed to assess the knowledge and practices of clinicians and laboratory scientists on the use of saliva for clinical or laboratory tests. Methods This was a cross-sectional survey of health care workers (100 clinicians and 62 laboratory scientists) closely involved with specimen collection for clinical and laboratory investigation at two health facilities (secondary and tertiary) in Nigeria. Information was obtained from participants using pretested structured questionnaires. Data were analyzed with SPSS and level of significance set at p < 5%. Results The mean age of the study participants was 34.1 (±6.6) years. The majority (95.7%) knew saliva could be used for clinical/laboratory test. A higher proportion of laboratory scientists knew saliva could be used in diagnosing HIV (59.2%), oral diseases (88.7%), oro-facial tumors (64.4%) and genetic testing (94.5%) compared to (41%), (80%), (40%) and (80%), of clinicians respectively (p < 0.05). More clinicians (85%) indicated saliva as a good specimen for diagnosing systemic diseases compared with scientists (63%), p < 0.001. Saliva was the most comfortable/convenient body fluid to obtain from patients with more clinicians (80%) mentioning this than scientists (49.1%), p < 0.001. Twenty-six clinicians had used saliva for disease diagnosis (64%), treatment monitoring (28%) or research purposes (8%). Saliva sampling for research purposes was more prevalent among clinicians (p = 0.004). Conclusion The majority of the health care workers knew the various uses and advantages of saliva as a specimen for clinical and laboratory investigation. However, few indicated previous use for clinical and laboratory investigation especially in the area of research.


Introduction
Prompt disease diagnosis is not only relevant to reduce disease severity and prevent complications, but also crucial to achieve good success rate of therapy [1]. A great need exists for convenient and accurate point-of-care diagnostic tools that can be used in a non-invasive manner. This is of particular relevance in the developing world, where many health risks and illnesses remain poorly defined [2]. Saliva has been studied extensively as a potential diagnostic tool over the last decade due to its ease and non-invasive accessibility along with its abundance of biomarkers, such as genetic material and proteins [3][4][5][6][7]. Clinical practice and research rely on the collection of different body fluids including blood, saliva and urine to answer important questions about patients' health and risk status. In addition, federal and industrial funding sources have been used to develop saliva-based diagnostic tests [2,3] and considerable progress has been made to elucidate the applicability of human saliva for disease diagnostics and monitoring [8][9][10][11]. However, its use for clinical or laboratory tests is still subject to the awareness as well as the acceptability of the concerned population especially the healthcare providers. No previous study on the knowledge and practices of healthcare workers on the use of saliva and other body fluids (blood and urine) for clinical testing has been documented from our environment. In addition, there is need for data to support the use of saliva over other traditional diagnostic fluids for clinical testing.
The findings from this study may indicate health care workers' level of awareness of and receptivity towards saliva-based tests and probably health care workers based evidence in support of the reported ease of collection and point of care applicability of saliva testing. Thus, this study aimed at assessing the knowledge and practices of health care workers on the use of saliva for clinical and laboratory tests.

Methods
This study received ethical approval from the Institution's Ethics Committee with approval number UI/UCH/EC/13/0099. It was a descriptive cross-sectional survey carried out at two health care facilities (one tertiary and the other a secondary health care facility) in Ibadan, Oyo State, Nigeria. All consenting clinicians and medical laboratory scientists available at the two health facilities during the period of the study were included. A convenience sampling technique was used to recruit the study participants at the two health care facilities. Information on biodata of the participants and their views on the use of saliva in clinical and laboratory testing were collected through structured questionnaires. The questions on the biodata of the participants were on their age, gender, profession and place of practice. The questionnaire assessed knowledge and practices of the participants on the use of saliva in clinical and laboratory testing, sources of this knowledge, the diseases that it can be used to investigate and diagnose, their preferred choice of sample collection among saliva and other body fluids, perceived advantages of saliva over other body fluids and previous saliva sampling for disease diagnosis and monitoring as well as research purposes. The questionnaire was self-administered and it was pretested among 20 clinicians and 10 laboratory scientists in the two facilities who were excluded from the main study to validate the questionnaire and determine the ease of answering the questions as well as the comprehensiveness. Prior to administration of the questionnaire, the purpose of the study was explained and only consenting health care workers were recruited for the study. Interns as well as doctors or scientists who were not available at the time of study were excluded.
Data obtained was subjected to statistical analyses using SPSS version 23. Categorical data were summarized with frequencies and percentages and compared with chi square while quantitative data were summarized as means ± standard deviations (SD). For the purpose of bivariate analysis, age was dichotomized using the mean age. The p value for statistical significance was at < 0.05.

Results
The mean age of the study participants was 34.  Table 2). The advantages of saliva over other body fluid specimen, which the study participants strongly agreed or agreed with included; ease of collection (94.9%), elimination of fear of prick (92.5%) lower cost of sample collection (79.8%), reduced risk of infection (78.6%) and requirement of little or no skills for collection (75.1%). A higher proportion of clinicians (49%) indicated that saliva collection required no special skill compared to scientists (24.5%), p = 0.002. Saliva was the most preferred specimen to collect from patients by clinicians (44.0%), while blood specimen was preferred by scientists (46.4%). However, blood samples were the most preferred specimen to collect compared with other body fluids (Table 3). Of all the specimen, saliva was the most comfortable and convenient to obtain from patients and more clinicians (80%) mentioned this than scientists (49.1%), p < 0.001.
In rating the level of convenience in specimen collection by the health care workers; scientists believed that blood samples and urine specimens were more convenient to collect than saliva samples (Table   3). Methods used by clinicians to collect saliva sample included spitting into specimen bottles (68.0%), use of cotton wool rolls

Discussion
To the best of our knowledge this study is the first to report the antibodies, proteins, hormones, cytokines, and a variety of diseasespecific biomarkers. There has been increasing knowledge about the use of saliva for clinical and laboratory diagnosis as observed in this study and previous reports [12][13][14][15]. This increased awareness is possibly the outcome of numerous reports on the use of saliva for the diagnosis as well as monitoring of oral and systemic diseases [16][17][18]. More importantly, if it is possible to obtain similar or identical information with saliva sample that is easy to collect and that does not require invasive procedures, the need for a blood draw would become unnecessary. This is particularly important in a number of populations and situations, which include handling pediatric and geriatric patients, or when access to health care is limited in remote geographic areas or rural communities where phlebotomists are unavailable. Similar to our finding, a survey reported that dentists believed that screening for medical conditions (in the dental clinics) is important and they indicated willingness to participate when the sample is saliva, as opposed to a finger stick [19]. Of the various methods of saliva collection, spitting into specimen bottles was the most common method used by the clinician respondents in this study, whereas use of mechanical collector was the least method indicated. This finding agrees with many reports [6,7,16,18] that used saliva samples and this could be attributed to the fact that the spitting method is more convenient and less expensive compared to the other methods. For example, use of mechanical collector or device requires a selection of commercially available devices for the collection and some of these devices are not readily available in the developing countries. Also, using this method may result in spending more money for the procurement of the materials, which might end up making it more expensive. Of all the types of specimen, saliva was chosen as the most comfortable and convenient to obtain from patients and more clinicians mentioned this than scientists. However, blood samples were the most preferred specimen to collect compared with other body fluids (blood and urine). Saliva was the most preferred specimen to collect from patients by clinicians, while blood specimen was preferred by scientists. In addition, in rating the level of convenience in specimen collection by the health care workers; scientists believed that blood samples and urine specimens were more convenient to collect than saliva samples. This finding may be related to the non-familiarity of the scientists with saliva sampling due to the fact that only a few of the scientists also indicated that they have collected saliva samples before. The saliva samples collected by clinicians from patients were used mostly for disease diagnosis rather than for research and treatment monitoring. In addition, saliva collection as samples for research purposes was practiced more often by clinicians than scientists. These findings indicate the necessity for the increased use of saliva samples in research activities by clinicians and scientists, more so that saliva has many constituents that can be explored.
Importantly, the advent of modern technology and current development of diagnostic biomarkers via proteomic and genomic approaches has broadened the use of saliva for various analyses that can be used in making clinical decisions and predicting treatment outcomes [2,4,5]. Along with these developments are advancements to overcome barriers such as technological problems related to achieving high sensitivity, high specificity, miniaturization, high throughput (assay of a large number of samples concurrently), automation, portability, low cost, high functionality and speed [2].
Overcoming these barriers will encourage widespread implementation of salivary diagnostics by the clinicians and scientists.
Diseases and conditions that saliva specimen had been collected from patients and used to investigate included oral diseases (32.0%), systemic diseases (28.0%), HIV (12.0%), genetic testing (8.0%) and others (20.0%) like tuberculosis, urea monitoring, respiratory tract infections, oral microbial isolation and acid phosphatase analysis.
These findings indicate that there is still a large vacuum in the use of saliva for important diagnostic uses. This may be attributed to the lack of facilities and appropriate funding for research activities in our environment. Also, the low patronage of use of saliva for disease diagnosis as indicated in this survey may be explained by lack of correlation between plasma and saliva levels of some parameters. For example, the second major use of saliva samples is for the quantitation of steroid hormone levels. Assays have shown consistent accurate detection of hormones such as cortisol, estriol, estrogen and testosterone [20][21][22][23]. However, salivary levels do not correlate well with serum levels in the case of conjugated steroid hormones [24].
These observations raise the general issue of a qualitative versus quantitative assay for biomarkers in saliva. When qualitative (such as absent versus present or yes versus no) results are needed, as in the case of malarial parasite, pregnancy, bacterial and viral infections, saliva sampling will mostly be useful. When a quantitative result is needed however, for example when evaluating levels or concentrations of parameters such as glucose, DHEA-S, creatinine, urea etc, the determination of the saliva/plasma ratio is necessary.
The closer the saliva/plasma ratio to 1 (e.g. as for ethyl alcohol and unconjugated steroid hormones), the more feasible the quantitative salivary testing for the parameter and if not, then a quantitative salivary-based assay of that parameter may not be suitable for that biomarker [24].  Tables   Table 1: sources of knowledge of saliva as sample for investigation