In vitro diagnostic company recalls and medical laboratory practices: an Italian case

Is it True Hypoparathyroidism? A Root Cause Analysis of Unusually Low Intact Parathyroid Hormone (iPTH) at a Clinical Laboratory

INTRODUCTION

Intact Parathyroid Hormone (iPTH) has a short half-life i.e. two to four minutes therefore the sampling regimen has to pass through a stringent pre-analytical process control. The aim of this study was to identify the causes of apparently falsely low iPTH encountered while signing out Laboratory reports by the Clinical Chemistry professionals.

MATERIAL AND METHODS

This report was conducted at the section of Clinical Chemistry, The Aga Khan University Hospital (AKUH) Karachi Pakistan from July to December 2017. Audit tool utilized was Plan-Do-Check-Act Cycle. After correlating with available clinical details and lab parameters, all low iPTH values (<16 pg/ml) were investigated by phone interview. A fresh sample was requested for non-correlating cases.Appropriate interventions were undertaken and a re-assessment was done from January to March 2018.

RESULTS

During the audit, 2559 iPTH samples were analyzed. 110 (4.3%) were identified as apparently falsely low. After recollection, the above 110 samples were immediately centrifuged, and cold chain maintained until re-analysis. 60 (2.4%) resulted with normal or elevated levels. The causes identified were poor compliance of staff with pre-analytical steps including delayed sample separation and unfavorable temperature chain maintenance. Interventions included online meetings with the staff country-wide and circulation of flyers detailing the pre-analytical steps via emails and hard copies. Re-audit showed reduction in number of apparently falsely low results to 30 out of a total of 1448 samples and 14 (0.96%) were investigated to be falsely low.

CONCLUSION

Stringent pre-analytical process control is vital for quality reporting and patient safety.

Rejection of hemolyzed samples can jeopardize patient safety

INTRODUCTION

In vitro hemolysis is the primary cause of sample/test rejection by the laboratory.

CASE REPORT

A 10-year-old, admitted with an asthma attack in the emergency-room, medicated with albuterol sulphate (intravenous bronchodilator that could induce hypokalemia), needed laboratory test monitoring. The physician prescribed the technical-nurse to perform blood sampling for: complete blood count, electrolytes, glucose, and blood gas analysis-within 30min after therapy. Samples were delivered to laboratory with a note "I had difficult to locate an appropriate access to perform the blood collection".

LABORATORY RESULTS

Glucose: 4.77 mmol/L. Complete blood count revealed discreet eosinophilia 0.13x10⁹/L, and thrombocytopenia 18x10⁹/L. However, platelet clumps were observed in peripheral blood smear. Blood gas analysis was unreported, laboratory informed that sample had micro clots.Electrolytes: laboratory did not report the results; sample hemolyzed. 0.9 g/L of free hemoglobin is the cut-off defined by the laboratory; the sample presented 2.3 g/L of free hemoglobin. 3.9 mmol/L of potassium was the unreported result vs 2.1 mmol/L in the new sample.Briefly, the laboratory technician was trained to hide potassium results on hemolyzed sample due to the potential overestimation. Even if the hemolyzed sample presented a potassium value close to the lower reference range value (3.5-5.1 mmol/L), reporting the potassium result could allow the physician starting proper therapy to revert the hypokalemia by albuterol sulfate.

CONCLUSION

The laboratory should be aware of the clinical patient conditions and of the related physician needs, before hiding results. Therefore, both the laboratory and the clinic personnel should communicate in order to guarantee the patient safety.

Can chewing gum be another source of preanalytical variability in fasting outpatients?

INTRODUCTION

In the daily laboratory practice, there are patients coming to blood collection sites chewing sugar-free gum, considering it irrelevant to laboratory tests. The aim of this study was to evaluate whether a sugar-free chewing gum can interfere with laboratory tests.

METHODS

We studied 22 healthy volunteers. After a 12-hour overnight fasting, the first blood sample was collected between 8:00 and 8:30 a.m. Then, immediately after the first venous blood collection, the subjects started chewing the gum (declared sugar-free) for 20 min. Subsequent venous blood samples were collected at 1, 2, and 4 hours after chewing the gum. Significant differences between samples were assessed by the Wilcoxon ranked-pairs test.

RESULTS

Among all the results, statistically significant differences (p < 0.05) between basal and × hours after chewing sugar-free gum were observed for the following parameters: cortisol, insulin, C-peptide, triglycerides, uric acid, urea, amylase, alanine aminotransferase, lipase, creatine kinase, total bilirubin, direct bilirubin, phosphate, iron, potassium, thyroid stimulating hormone, red blood cell count, hematocrit, hemoglobin, mean cell volume, red cell distribution width, white blood cell count, lymphocytes, neutrophils, and eosinophils; whereas, coagulation tests were not impacted by chewing sugar-free gum.

CONCLUSIONS

We recommend instructing the patients to avoid the use of chewing gum before blood collection for laboratory tests.

Sample Management: Stability of Plasma and Serum on Different Storage Conditions

BACKGROUND AND OBJECTIVE

The analytes stability on serum and plasma are critical for clinical laboratory, especially if there is a delay in their processing or if they need to be stored for future research. The objective of this research was to determine the stability of K3EDTA-plasma and serum on different storage conditions.

MATERIALS AND METHODS

A total of thirty healthy adults were studied. The serum/plasma samples were centrifuged at 2000g for 10 minutes. Immediately after centrifugation, the serum/plasma analytes were assayed in primary tubes using a Cobas c501 analyzer (T0); the residual serum/plasma was stored at either 2-8°C or -20°C for 15 (T15) and 30 days (T30).Mean concentrations changes in respect of initial concentrations (T0) and the reference change values were calculated. For assessing statistical difference between samples, the Wilcoxon ranked-pairs test was applied.

RESULTS

We evidenced instability for total bilirubin, uric acid, creatinine and glucose at T15 and T30 and stored at -20°C (p<0.05). However, potential clinical impact significance were observed only for total bilirrubin T30 at -20°C, and creatinine T30 at 2-8°C.

CONCLUSIONS

Our results had shown that storage samples at -20°C is a better way to preserve glucose, creatinine, and uric acid. Therefore, laboratories should freeze their samples as soon as possible to guarantee proper stability when there is need to repeat analysis, verify a result, or add a laboratory testing.

Causes of Preanalytical Interferences on Laboratory Immunoassays - A Critical Review

The immunoassays methods need avoiding interferences that can influence result interpretation. Main sources of interference arise from either patient status, preparation and physiology or laboratory process and procedures. The aim of this non-systematic critical review is to highlight the preanalytical interferences on laboratory immunoassays. Blood hormone profile changes according with age and depending on sex: these are important variables, mainly in newborn, during both sexual maturation and childbearing. Gonadotropins FSH and LH show a sharp increase with age in females, whereas in males LH appears rather stable. With age both males and females show progressive decay of the hormone profile. Stress causes variations, as it influences GH, prolactin, Cortisol and the total/free ratio of thyroid hormone. Diurnal variations, day of cycle, influence by estrogens on thyroid hormone are relevant for result variability. Paraproteins and autoantibodies can interfere in some assays particularly drug, vitamin D and thyroid hormone. As regards the variables due to sample matrix, and to evacuated tubes components, some additives and anticoagulants have been reported to influence specific assays, e.g. thyroid hormone. Hemolysis, lipemia and bilirubin cause interferences on specific techniques/tests, e.g. ferritin, TSH, Vitamin B12, progesterone and folic acid. Nicotine and cocaine addictions interfere with some hormones. Thus, laboratory professionals should be aware of preanalytical problems particularly important when dealing with the immunoassays, by taking appropriate actions to avoid any relevant interferences.

Breakfast can Affect Routine Hematology and Coagulation Laboratory Testing: An Evaluation on Behalf of COLABIOCLI WG-PRE-LATAM

Laboratories worldwide perform both hematological and coagulation testing on patients avoiding fasting time. In 2017, the Latin America Confederation of Clinical Biochemistry (COLABIOCLI) commissioned the Latin American Working Group for Preanalytical Phase (WG-PRE-LATAM) to study preanalytical variability and establish guidelines for preanalytical procedures to be applied by clinical laboratories and health care professionals. This study, on behalf of COLABIOCLI WG-PRE-LATAM, aims to evaluate the effect of the breakfast on routine hematology and coagulation laboratory testing. We studied 20 healthy volunteers who consumed a breakfast containing a standardized amount of carbohydrates, proteins, and lipids. We collected blood specimens for routine hematology and coagulation laboratory testing before breakfast and 1, 2, and 4 hours thereafter. Significant differences between samples were assessed by the Wilcoxon ranked-pairs test. Statistically significant differences ( p  < 0.05) between basal and 4 hours after the breakfast were observed for red blood cells, hemoglobin, hematocrit, mean corpuscular volume, white blood cells, neutrophils, lymphocytes, monocytes, mean platelet volume, and activated partial thromboplastin time. In conclusion, the significant variations observed in several hematological parameters, and activated partial thromboplastin time due to breakfast feeding demonstrate that the fasting time needs to be carefully considered prior to performing routine hematological and coagulation testing to avoid interpretive mistakes of test results, and to guarantee patient safety. Therefore, COLABIOCLI WG-PRE-LATAM encourages laboratory quality managers to standardize the fasting requirements in their laboratory, i.e., 12 hours.

Impact of an Andean breakfast on biochemistry and immunochemistry laboratory tests: an evaluation on behalf COLABIOCLI WG-PRE-LATAM

Introduction

In Andean countries, specifically in Ecuador, a food transition in the population has been observed because of economic growth. The Working Group for Preanalytical Phase in Latin America (WG-PRE-LATAM) of the Latin America Confederation of Clinical Biochemistry (COLABIOCLI) was established in 2017, and its main purpose is to study preanalytical variability and establish guidelines for preanalytical procedures in order to be implemented by clinical laboratories and healthcare professionals in Latin America. The aim of this study on behalf of COLABIOCLI WG-PRE-LATAM was to evaluate whether an Andean breakfast can interfere with routine biochemistry and immunochemistry laboratory tests.

Materials and methods

We studied 20 healthy volunteers who consumed an Andean breakfast containing a standardized amount of carbohydrates, proteins and lipids. We collected blood specimens for laboratory tests before breakfast and 1, 2, and 4 hours thereafter. Significant differences between samples were assessed by the Wilcoxon ranked-pairs test.

Results

The Andean breakfast statistically (P ≤ 0.05), modified the results of the following tests: triglycerides, insulin, cortisol, thyroid stimulating hormone, free thyroxine, total protein, albumin, urea, creatinine, lactate dehydrogenase, alkaline phosphatase, amylase, lipase, total bilirubin, direct bilirubin, iron, calcium, phosphorus, magnesium, and uric acid.

Conclusions

Andean breakfast can influence the routine biochemistry and immunochemistry laboratory tests and might expose patient safety to some risks. Therefore, the COLABIOCLI WG-PRE-LATAM calls attention and highlights that the fasting time needs to be carefully considered when performing blood testing in order to prevent spurious results and thus, reduce laboratory errors.

The impact of fist clenching and its maintenance during venipuncture on routine hematology testing

BACKGROUND

Prevention of a disturbance of the blood vessel allows phlebotomists to collect a blood specimen by venipuncture that will truly mirror the patient condition. This study was aimed to evaluate the impact of repeated fist clenching and maintenance of the fist during blood collection by venipuncture for routine hematology testing.

METHODS

Blood were collected from 16 healthy volunteers with two separate sequential procedures, entailing standard venipuncture with hand opened throughout blood collection, or clenching the fist six times before venipuncture and maintaining the fist until completion of blood collection. The parameters tested included red blood cell (RBC) count, hemoglobin, hematocrit, mean corpuscular volume (MCV), RBC distribution width, white blood cell count and differential, including neutrophils, lymphocytes, monocytes, eosinophils, basophils, large unstained cells, platelet count, mean platelet volume, and reticulocytes. The results were reported as median and interquartile range. The comparison of data obtained with the two different venipuncture procedures (i.e., with or without fist clenching and closed hand) was performed with Wilcoxon-Mann-Whitney ranked-pairs test. The degree of statistical significance was set at P<.01.

RESULTS AND CONCLUSION

Fist clenching and maintenance during blood collection for routine hematology testing was effective to increase the MCV by 1.2% (P<.001). All others hematological parameters were not significantly biased by fist clenching, though hematocrit, neutrophils, eosinophils, and reticulocytes displayed mindful of trends. We hence advise patients against clenching their fist before blood collection for hematology testing.