Volume 44, Issue 3

Objectives Clinical laboratory analyses are essential part of critical care. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)/coronavirus disease 2019 (COVID-19)-confirmed cases were doubling in Germany every 3 days during March 2020. Health care systems are preparing for an epidemic crisis. Methods We outline a cohort-based emergency planning. The plan is based on three independent self-sufficient cohorts that maintain duty for 7 days, followed by quarantine-like rest for 14 days. COVID-19-infected and otherwise ill personnel will be replaced by a tactical reserve, which is again replaced by recovered staff. Results We switched to the outlined system when incidence of confirmed COVID-19 cases surpassed 50/100,000 residents. Our parameter spectrum was reduced to the essential analyses in agreement with our clinical colleagues. So far the system works well. In model calculations, the system is robust to maintain essential laboratory functionality even when incidence of COVID-19 is higher than that currently observed in the most severely hit countries. Conclusions We outline a cohort-based emergency planning to maintain essential functionality of a clinical laboratory while minimizing the risk of spreading infection with COVID-19 among our workforce during the COVID-19 epidemic faced in 2020.

It is well documented that in the chain from sample to the result in a clinical laboratory, the pre-analytical phase is the weakest and most vulnerable link. This also holds for the use and analysis of extracellular nucleic acids. In this short review, we will summarize and critically evaluate the most important steps of the pre-analytical phase, i.e. the choice of the best control population for the patients to be analyzed, the actual blood draw, the choice of tubes for blood drawing, the impact of delayed processing of blood samples, the best method for getting rid of cells and debris, the choice of matrix, i.e. plasma vs. serum vs. other body fluids, and the impact of long-term storage of cell-free liquids on the outcome. Even if the analysis of cell-free nucleic acids has already become a routine application in the area of non-invasive prenatal screening (NIPS) and in the care of cancer patients (search for resistance mutations in the EGFR gene), there are still many unresolved issues of the pre-analytical phase which need to be urgently tackled.

The identification of a suitable distribution model is a prerequisite for the parametric estimation of reference intervals and other statistical laboratory tasks. Classification of normal vs. lognormal distributions from healthy populations is easy, but from mixed populations, containing unknown proportions of abnormal results, it is challenging. We demonstrate that Bowley’s skewness coefficient differentiates between normal and lognormal distributions. This classifier is robust and easy to calculate from the quartiles Q 1– Q 3 according to the formula ( Q 1 − 2 ·  Q 2 +  Q 3)/( Q 3 −  Q 1). We validate our algorithm with a more complex procedure, which optimizes the exponent λ of a power transformation. As a practical application, we show that Bowley’s skewness coefficient is suited selecting the adequate distribution model for the estimation of reference limits according to a recent International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) recommendation, especially if the data is right-skewed.

Objectives To evaluate the value of liquid-based cell examination combined with human papillomavirus (HPV) genotypes in the detection of cervical intraepithelial neoplasia. Methods A total of 21,155 patients who had undergone cytology, HPV genotypes and colposcopy-guided biopsy were grouped into three groups. Sensitivity, specificity, positive predictive value, and negative predictive value of the test methods of the three groups were compared. Results In the age group of less than 50 years, the sensitivity of HPV genotype testing was significantly higher than that of liquid-based cytology. The specificity of liquid-based cytology was significantly higher in all age groups than that of HPV genotype testing. The positive predictive value of each test index was higher in the age group less than 30 years, and the negative predictive value was higher in the 30–50-year age groups. In different age groups, liquid-based cytology and HPV genotype combined method can improve the sensitivity of detection and negative predictive values. Conclusions The HPV test has higher sensitivity and negative predictive value, and the cytology method is relatively specific and less sensitive. The combined method has better sensitivity and negative predictive value.

Background Although the concentration of uric acid in serum or plasma is known to depend on sex and age and is subject to diurnal variation, the influence of these covariates on the reference interval (RI) is often neglected. Consequently, the values in the literature vary considerably. Therefore, we reinvestigated the reference limits and their dependence on covariates. Methods A new indirect approach was applied which derives a continuous function between age and RIs avoiding the usual “jumps” between various age groups. Results It is confirmed that the uric acid concentration in women is lower than in men. The RIs increase with age, in women more than in men. Between 80 and 90 years of age, the upper RI limit (RL) approximately reaches the same level in both sexes. Because the uric acid concentration may indicate renal insufficiency, the concentrations of creatinine and cystatin C were also measured. Both measurands showed the same behaviour as uric acid. Therefore, the age and sex dependency should be considered if the uric acid concentration is used as an indicator for hyperuricaemia (e.g. caused by gout or other metabolic diseases). Furthermore, a diurnal variation was observed. Conclusions Due to the variations of various covariates (age, sex, daytime, analytical systems), it is recommended that each laboratory should estimate its own RIs.

Objectives The BD MAX Check-Points CPO Assay (BD MAX CPO Assay; BD, The Netherlands) is a diagnostic test designed for the rapid detection and differentiation of the bla KPC , bla NDM , bla VIM / bla IMP-1 , and bla OXA-48 genes. We verified the performance of the BD MAX CPO Assay to implement it in the clinical laboratory. Methods A total of 113 bacterial isolates collected from various clinical specimens harboring carbapenemase genes as confirmed by polymerase chain reaction (PCR) and sequencing were evaluated. The results of the BD MAX CPO Assay were compared to previously confirmed results. Results All results of the BD MAX CPO Assay were concordant with previous results; 61 Klebsiella pneumoniae carbapenemase (KPC), 40 New Delhi metallo-β-lactamase (NDM), three oxacillinase-48 (OXA-48)-like, two imipenem (IMP), and four multiple carbapenemase genes (one KPC/NDM, three NDM/OXA) were detected by the BD MAX CPO Assay. Three non-carbapenemase-producing carbapenem-resistant Enterobacteriaceae isolates were negative. Conclusions The BD MAX CPO Assay can be used to identify carbapenemase gene in bacterial isolates cultured from clinical specimens in the clinical laboratory.

Background Urinalysis is one of the most commonly performed tests in clinical practice and supplies important information for a series of clinical conditions, including renal and urinary tract diseases. The clinical laboratory often completes urinalysis through the combined use of urinary dry-chemistry and formed-element analyzers. Urine red blood cell (RBC) morphology test is often used to discriminate the source of hematuria by manual microscopy. Case presentation In this case report, we describe a 39-year-old woman with chronic glomerulonephritis (CGN) who underwent both urine routine test and RBC morphology test. Her RBC count was in the normal range and the occult blood test was negative in routine test, while the RBC morphology test indicated the presence of non-homogeneous hematuria. Conclusions Therefore, we analyzed the causes of false-negative result on the urine chemical analyzer and the automatic microscope system, respectively.