H Spirometry Reference Value Calculator | NIOSH | CDC How can I improve the air quality in my home? 5. I feel that hypoxemia is caused by the presence of low V/Q area rather than high V/Q. You are currently on the The prevalence is approximately 5%, and the condition may improve when amiodarone is stopped, with or without adding systemic corticosteroids. This elevated pressure tends to reduce the capillary blood volume a bit further. A gas transfer test measures how your lungs take up oxygen from the air you breathe. Inhaled CO is used because of its very high affinity for hemoglobin. When factored in with a decrease in alveolar volume (which decreases the amount of CO available to be transferred), the rate at which CO decreases during breath-holding (for which KCO is an index) increases. Single breath methods are used to determine the rate constant of the alveolar uptake of carbon monoxide (CO) for 10 s at barometric pressure, that is, transfer coefficient of the lung for CO (Kco) and alveolar volume (V A) (Krogh, 1915; Hughes and Pride, 2012).Kco more sensitively reflects the uptake efficiency of alveolar-capillary The results will depend on your age, height, sex and ethnicity as well as the level of haemoglobin in your blood. To see content specific to your location, In addition, there is an implicit assumption is that DLCO was normal to begin with. Oxbridge Solutions Ltd. Creative Commons Attribution-NonCommercial 4.0 International License. 2006, Blackwell Publishing. This estimates the lung surface area available for gas exchange. extra-parenchymal restriction such as pleural, chest wall or neuromuscular disease), an increase in pulmonary blood flow from areas of diffuse (pneumonectomy) or localized (local destructive lesions/atelectasis) loss of gas exchange units to areas with preserved parenchyma; this frequently leads to more modest increases in KCO (although a high KCO can also be seen with normal VA when there is "increased pulmonary blood flow" or redistribution (e.g. 0000126688 00000 n Additionally, Dlco may predict mortality in a variety of lung diseases (including cancer), various ILDs (including idiopathic pulmonary fibrosis), and severe PAH. Z-iTr)Rrqgvf76__>dJ&x\H7YOpdDK|XYkEiQiKz[X)01aNLCPe.L&>\?0Gf~{LVk&k~7uQ>]%"R0.Lg'7iJ-EYu3Ivx};.e@IbSlu}&kDiqq~6CM=BFRFnre8P+n35f(PVUy4Rq89J%,WNl\Te3. Carbon monoxide transfer coefficient | Radiology Reference decreased DMCO). 0000022334 00000 n Not really, but it brings up an interesting point and that is that the VA/TLC ratio indicates how much of the lung actually received the DLCO test gas mixture (at least for the purposes of the DLCO calculation). 0000017721 00000 n The Fick law of diffusion can explain factors that influence the diffusion of gas across the alveolar-capillary barrier: V is volume of gas diffusing, A is surface area, D is the diffusion coefficient of gas, T is the thickness of the barrier, and P1P2 is the partial pressure difference of gas across the alveolar-capillary barrier. The uptake of CO can be calculated from the Va and inspired and expired CO concentrations. 0000055053 00000 n Its sad that the partnership approach with patient and professional is leaving you completely out of the loop . Simply put, Dlco is the product of 2 primary measurements, the surface area of the lung available for gas exchange (Va) and the rate of alveolar capillary blood CO uptake (Kco). K co and V a values should be available to clinicians, as fundamental to understanding the clinical implications of D lCO. Dyspnea is the most common reason for ordering a Dlco test, but there are many situations and presentations in which a higher than predicted or lower than predicted Dlco suggests the possible presence of lung or heart disease (Table 1). How will I recover if Ive had coronavirus? <]>> When you know the volume of the lung that youre measuring, then knowing the breath-holding time and the inspired and expired carbon monoxide concentrations allows you to calculate DLCO in ml/min/mmHg. This ensures that Dlco remains relatively constant at various volumes from tidal breathing to TLC. In particular, consider also the ratio between alveolar volume and pulmonary capillary volume at TLC and FRC. WebK co will be greater than 120% predicted in case 1, 100120% in case 2, and 40120% in case 3, depending on pathology. uuid:8e0822dc-1dd2-11b2-0a00-cb09275d6100 Kco is not the lung CO diffusing capacity. X, Most people have a diagnosis such as copd so hopefully you will get yours soon. If we chose different DLCO and TLC reference equations wed have a different predicted KCO. Transfer coefficient of the lung for carbon monoxide and the accessible alveolar volume: clinically useful if used wisely. Respir Med 2007; 101: 989-994. Dlco can be normal or slightly decreased in extrinsic restrictive disorders (underlying lung physiology is normal except for atelectasis) such as Guillain-Barr syndrome, myasthenia gravis, amyotrophic lateral sclerosis, and corticosteroid-induced myopathy, given a decrease in Va but a normal to elevated Kco (Dlco/Va). A fit young adult may have a KCO of approximately 1.75 mmol/min/kPa/litre, an elderly I):;kY+Y[Y71uS!>T:ALVPv]@1 tl6 Part of the reason for this is that surface area does not decrease at the same rate as lung volume. Best, He requested a ct scan which I had today ( no results) to 'ensure there is no lung parenchymal involvement'. J.M.B. 186 (2): 132-9. At the time the article was created Yuranga Weerakkody had no recorded disclosures. For the COPD patients at least part of the improvement was due to an increase in the measured VA. However, I am not sure if my thoughts are correct because in patients with PVOD/PCH KCO is severely reduced in most cases. 9 This typically amounts to less than 5% of all white blood cells. The normal values for KCO are dependent on age and sex. The term Dlco/Va is best avoided because Kco (the preferred term) is not derived from measurement of either Dlco or Va! Subgroups of patients with asthma, emphysema, extrapulmonary lung disease, interstitial lung disease and lung resection were identified. 16 0 obj Webelevated Kco levels, DACOand KACO levels are normal. Using helium as the inert gas, the concentration of the inhaled helium (He, Vi is the volume of inhaled gas minus the estimated dead space (since dead space will not contain any helium). A reduced Dlco also can accompany drug-induced lung diseases. eE?_2/e8a(j(D*\ NsPqBelaxd klC-7mBs8@ipryr[#OvAkfq]PzCT.B`0IMCruaCN{;-QDjZ.X=;j 3uP jW8Ip#nB&a"b^jMy0]2@,oB?nQ{>P-h;d1z &5U(m NZf-`K8@(B"t6p1~SsHi)E Spirometry is performed simultaneously with measurement of test gas concentrations in order to calculate Va and Kco to derive Dlco, which then is adjusted for hemoglobin concentration. Your statement above: Near TLC Simultaneously however, the pulmonary capillaries are also stretched and narrowed and the pulmonary capillary blood volume is at its lowest -doesnt really comply with this. The normal values for KCO are dependent on age and sex. A more complex answer is that because vascular resistance increases, cardiac output will be diverted to the pulmonary circulation with the lowest resistance. VA (alveolar volume). Because it is not possible to determine the reason for either a low or a high KCO this places a significant limitation on its usefulness. Top tips for organising a brilliant charity quiz, Incredible support from trusts and foundations, Gwybodaeth yng Nghymraeg / Welsh language health information, The Asthma UK and British Lung Foundation Partnership, Why you'll love working with the British Lung Foundation, Thank you for supporting the British Lung Foundation helpline. When you remove the volume of the lung from the equation however (which is what happens when you divide DLCO by VA), all you can measure is how quickly carbon monoxide decreases during breath-holding (KCO). It may also be used to assess your lungs before surgery, or to see how a persons lungs react when having chemotherapy. KCO is probably most useful for assessing restrictive lung diseases and much that has been written about KCO is in reference to them. Hence, seeing a low Kco would be a clue that the patient with neuromuscular disease has a concomitant disease or disorder that impairs gas exchange (ie, pulmonary fibrosis or pulmonary vascular disease) on top of the lower alveolar volume. This means that when TLC is reduced but the lung tissue is normal, which would be the case with neuromuscular diseases or chest wall diseases, then KCO should be increased. Despite this KCO has the potential be useful but it must be remembered that it is only a measurement of how fast carbon monoxide disappears during breath-holding. endobj Current Heart Failure Reports. Examination of the carbon monoxide diffusing capacity (DLCO) in relation to its KCO and VA components. |0T2D17p*dl`R,8!^3;t4}a(0bk@|CFE;$4"r4b'7;4@27*'C tb9Cj Would be great to hear your thoughts on this! If so however, then for what are more or less mechanical reasons these factors could also contribute to a decrease in DLCO. A high KCO can be due to increased perfusion, a thinner alveolar-capillary membrane or by a decreased volume relative to the surface area. pE1 Last medically reviewed: January 2020. Carbon monoxide transfer coefficient (often abbreviated as KCO) is a parameter often performed as part of pulmonary function tests. Registered charity in England and Wales (326730), Scotland (SC038415) and the Isle of Man (1177). Apex PDFWriter Importance of adjusting carbon monoxide diffusing capacity (DLCO) and carbon monoxide transfer coefficient (KCO) for alveolar volume, Respir Med 2000; 94: 28-37. Other institutions may use 10% helium as the tracer gas instead of methane. The content herein is provided for informational purposes and does not replace the need to apply 0000014758 00000 n 1. The calculated VA therefore depends on where the tracer gas is measured during exhalation. DLCO studies should go beyond reporting measured, normal range The American Thoracic Society/European Respiratory Society statement on PFT interpretation advocates the use of a Dlco percent predicted of 80% as the normal cutoff. Caution in Interpretation of Abnormal Carbon Monoxide Diffusion This rate, kco, which has units of seconds, Confusion arises in how PFT laboratories, by convention, report Dlco and the related measurements Va and Dlco/Va. Acute respiratory distress syndrome (ARDS), Submit a review of our health information, Stories about living with a lung condition, Positions for obstructive lung conditions, Positions for restrictive lung conditions. Frans A, Nemery B, Veriter C, Lacquet L, Francis C. Effect of alveolar volume on the interpretation of single-breath DLCO. Any knowledge gratefully received. I'm hoping someone here could enlighten me. Does that mean that the DLCO is underestimated when the VA/TLC ratio is low? Thank you so much again for your comments. The use of the term DL/VA is probably a major contributor to the confusion surrounding this subject and for this reason it really should be banned and KCO substituted instead.]. Uvieghara AO, Lanza J, Vasudevan VP, Arjomand F. Volume correction for diffusion capacity: use of total lung capacity by either nitrogen washout or body plethymography instead of alveolar volume by single breath methane dilution. I am 49, never smoked, had immunosuppressant treatment for MS last year but otherwise healthy I had thought. When significant obstructive airways disease is present however, VA is often reduced because of ventilation inhomogeneity. Variability in how Dlco is reported is a concern. Transfer coefficient of the lung for carbon monoxide and the Check for errors and try again. An updated version will be available soon. [Note: The value calculated from DLCO/VA is related to Kroghs constant, K, and for this reason DL/VA is also known as KCO. 0000001116 00000 n For this reason, in my lab a KCO has to be at least 120 percent of predicted to be considered elevated (and I usually like it to be above 130% to be sufficiently Little use without discussion with your consultant. I called the Respiratory consultants secretary to inform her that I had had from my last post when I had to cancel my Lung Function test due to a chest infection. et al. 20 0 obj For the purpose of this study, a raised Kco was diagnosed only if it exceeded the predicted value for Kco (van The key questions that should be asked include: Is the reduction in Dlco due to a reduction in Va, Kco, or both? you and provide you with the best service. Your healthcare provider will explain your results and provide clarity if you have any questions. Dont worry if it takes several attempts to get a reliable reading. a change in concentration between inhaled and exhaled CO). This is because there is no loss of the gas through uptake by pulmonary tissues (as with oxygen) or into the capillary bed. pbM%:"b]./j\iqg93o7?mHAd _42F*?6o>U8yl>omGxT%}Lj0 This rate, kco, which has units of seconds-1, is calculated as follows: COo is the initial alveolar concentration, COe is the alveolar concentration at the end of the breath hold, and t is the breath-hold time in seconds. endobj A vital capacity (VC) of at least 1.5 L is required to perform the Dlco measurement with sufficient accuracy, because 0.75 to 1.0 L needs to be discarded as washout volume from dead space, and a Va sample of at least 500 mL must be available for calculating Dlco. When Dlco is below the predicted reference range (75% to 140% of predicted) it becomes a clue to the presence of a physiologic problem that ultimately may impair exercise, and even affect long-term survival from common lung diseases and disorders. HWMoFWTn[. In the low V/Q area, Hb will have difficulties in getting oxygen due to a relatively limited ventilated area. CO has a 200 to 250 times greater affinity for hemoglobin than does oxygen. Thank you so much for your help in this issue! 42 0 obj This by itself would be a simple reason for KCO to increase as lung volume decreases but the complete picture is a bit more complicated. independence. A normal Dlco does not rule out oxygen desaturation with exercise. The lung reaches its maximum surface area near TLC, and this is also when DLCO is at its maximum. 2 Different laboratories may have different normal reference ranges. 41 0 obj professional clinical judgement when diagnosing or treating any medical condition. 0000002233 00000 n good inspired volume). 0000049523 00000 n Simultaneously however, the pulmonary capillaries are also stretched and narrowed and the pulmonary capillary blood volume is at its lowest. Hughes JMB, Pride NB. The cause of the diffusion defect is a large scale V-Q mismatch but that doesnt look any different from somebody with PVOD/PCH with a DLCO and KCO that were 50% of predicted and where the V-Q mismatch is occurring on a much smaller scale. GPnotebook no longer supports Internet Explorer. WebThe equations for adjustment of predicted DLCO and KCO for alveolar volume are: DLCO/DL COtlc = 0.58 + 0.42 VA/VAtlc, KCO/KCOtlc = 0.42 + 0.58/(VA/VAtlc). http://www.atsjournals.org/doi/abs/10.1164/ajrccm-conference.2010.181.1_MeetingAbstracts.A2115. Similarly, disease states that result in loss of alveolar units, such as pneumonectomy, lobectomy, or lobar collapse as reflected by a low Va can reduce Dlco. Johnson DC. d K co will be greater than 120% predicted in case 1, 100120% in case 2, and 40120% in case 3, depending on pathology. At this time the alveolar membrane is stretched and at its thinnest which reduces the resistance to the transport of gases across the membrane. These are completely harmless at the very low levels used. 2023 Increases in DLCO are less common and appear to be mostly due to an increase in blood volume and/or cardiac output. Chest area is tender. The reason is that as the lung volume falls, Kco actually rises. It is an often misunderstood value and the most frequent misconception is that it is a way to determine the amount of diffusing capacity per unit of lung volume (and therefore a way to adjust DLCO for lung volume). 4 0 obj 105 (8): 1248-56. The results can be affected by smoking, so if you are a smoker, dont smoke for 24 hours before your test. 0 Blood flow of lost alveolar units can be diverted to the remaining units, resulting in a slight increase in Kco, and as a result, Dlco falls relatively less than expected given the reduction in Va. Emphysema or ILD can feature a loss of both Vc and Va, which can result in a more profound reduction in Dlco. Alone, Dlco is not enough to confirm the presence of or differentiate between the 2 lung conditions. To view profiles and participate in discussions please. This observation underscores the need for chest CT for confirming the diagnosis of ILD. Low lung efficiency is when This value is an expression of the gas transfer ability per unit volume of lung. D:20044910114917 The term DL/VA is misleading since the presence of VA implies that DL/VA is related to a lung volume when in fact there is no volume involved. A checklist can be helpful in establishing a regular routine for interpreting Dlco, Va and Kco (Tables 2 and3). Reference article, Radiopaedia.org (Accessed on 05 Mar 2023) https://doi.org/10.53347/rID-80732. Notify me of follow-up comments by email. For this reason, in my lab a KCO has to be at least 120 percent of predicted to be considered elevated (and I usually like it to be above 130% to be sufficiently confident). It also indicates that 79% to 60% of predicted is a mild reduction, 59% to 40% is a moderate reduction, and that Dlco values less than 40% of predicted are severely reduced.1. useGPnotebook. Overlooking a reduced Dlco can delay early diagnosis and treatment of a disease. tk[ !^,Y{k:3 0j4A{iHt {_lQ\XBHo>0>puuBND.k-(TwkB{{)[X$;TmNYh/hz3*XZ)c2_ WebThe normal values for KCO are dependent on age and sex. 0000014957 00000 n TLco refers to the transfer capacity of the lung, for the uptake of carbon monoxide (CO). Lam-Phuong Nguyen, DO, Richart W. Harper, MD, and Samuel Louie, MD. Hughes JMB, Pride NB. [43 0 R] It is also often written as DLCO/VA (diffusing capacity per liter of lung volume) and is an index of the efficiency of alveolar transfer of carbon monoxide. Respiratory Research 2013, 14:6), although I have some concerns about the substitution of DLNO for DMCO. The bottom line is that a reduced Dlco is not normal, requires explanation, and may indicate the presence of clinically significant lung disease or pulmonary vascular disease. x. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. A low VA/TLC ratio (less than 0.85) indicates that a significant ventilation inhomogeneity is likely present. 0000016132 00000 n This is why DL/VA (KCO!!! Breathing techniques for moving or lifting, Non-tuberculous mycobacterial infection (NTM), Connective tissue and autoimmune diseases, Pulmonary haemorrhage (bleeding into the lung), Your living with a lung condition stories, Northern Ireland manifesto: Fighting for Northern Ireland's Right to Breathe, Northern Ireland manifesto: live better with it, Stoptober: the 28-day stop smoking challenge, Take action on toxic air in Greater Manchester, How air pollution makes society more unequal, Invisible threat: air pollution in your area. In my labs software predicted KCO is derived from [predicted DLCO]/[Predicted TLC-deadspace] but the DLCO and TLC come from entirely different studies and different populations. Interstitial involvement in restrictive lung disease is often complicated and there can be multiple reasons for a decrease in DLCO. I am not sure whether my question is reasonable or not, 2. WebEnter Age, Height, Gender and Race. It also indicates that 79% to 60% of predicted is a mild reduction, 59% to 40% is a moderate reduction, and that Dlco values less than 40% of predicted are severely reduced. The ATS/ERS standards for DLCO of course contraindicate either Valsalva or Muller maneuvers during the breath-hold period because they do affect the pulmonary capillary blood volume (and therefore the DLCO). DLCO versus DLCO/VA as predictors of pulmonary gas exchange trailer COo Therefore, the rate of CO uptake is calculated from the difference between the initial and final alveolar CO concentrations over the period of a single breath-hold (10 seconds). Lam-Phuong Nguyen, DO, is chief fellow in the Division of Pulmonary, Critical Care, and Sleep Medicine in the Department of Internal Medicine at UC Davis Medical Center in Sacramento, California. 0000126796 00000 n Strictly speaking, when TLC is normal and the DLCO is reduced, then KCO will also be reduced. Intrinsic restrictive lung diseases such as ILD (specifically pulmonary fibrosis from collagen vascular disorders and sarcoidosis) commonly have a reduced Dlco. They helped me a lot! Here at Monash we use KCO as a way to assess what might be the cause of reduction in TLCO. to assess PFT results. Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them. If KCO is low with a low VA, then we also have to consider the possibility of reduction in alveolar volume (for whatever reason) in conjunction with parenchymal changes. A fit young adult may have a KCO of approximately 1.75 mmol/min/kPa/litre, an elderly adult may be about 1.25. 4 Required fields are marked *. 0000002029 00000 n 0000001782 00000 n Importance of adjusting carbon monoxide diffusing capacity (DLCO) and carbon monoxide transfer coefficient (KCO) for alveolar volume. To see Percent Prediced, you must enter observed FVC, FEV1, and FEF25-75% values in the appropriate boxes. I have had a lung function test which i am told is ok and my stats complaint and have just received a 21 page report plus a 7 page letter from the consultant. The diffusing capacity for nitric oxide (D lNO ), and the D lNO /D lCO ratio, provide additional insights. Diffusing capacity for carbon monoxide Asthma and Lung UK is a company limited by guarantee 01863614 (England and Wales). 0000126565 00000 n Your replies always impress me so much as your knowledge seems to know no bounds to the extent that I am curious. I wonder this: During INSPIRATION (at TLC) Ive learnt that the lung blood volume (LBV) increases due to a more negative intrathoracic pressure -> increased venous return to the RV -> increased lung filling AND reduced venous return to the LV -> reduced CO -> baroreceptor reflex -> reflex takycardia (to prevent drop in blood pressure). If your predicted KCO is derived from separate population studies I would wonder what effect re-calculating percent predicted DLCO and KCO using reference equations from a single study would have on your data and your expectations. 0000012865 00000 n Another common but underappreciated fact is that as lung volume falls from TLC to RV, Dlco does not fall as much as would be predicted based on the change in Va. Other drugs that can cause lung diseases include amphotericin, methotrexate, cyclophosphamide, nitrofurantoin, cocaine, bleomycin, tetracycline, and many of the newer biologics. For DLCO values that are close to the lower limit of the normal range (eg. Immune, Lipid Biomarkers May Predict Onset of Atopic Dermatitis in Infants, Treatment for Type 2 Diabetes Reduces Major CV Events in Men, Inflammation Reduction Medications May Lower Dementia Risk in Patients With Rheumatoid Arthritis, Sepsis Increases Risk of Post-Discharge Cardiovascular Events, Death, AHA Releases Statement on Hypertension Induced by Anticancer Therapy, Consultant360's Practical Updates in Primary Care. The inspired CO under these circumstances may not completely reach all the functioning alveolar-capillary units. A licensed medical 28 0 obj Realistically, the diagnosis of a reduced DLCO cannot proceed in isolation and a complete assessment requires spirometry and lung volume measurements as well. We use your comments to improve our information. Two, this would also lead to an increase in the velocity of blood flow and oxygen may not have sufficient time to diffuse completely because of the decrease in pulmonary capillary residence time. This could lead to a couple additional issues; one, that the depth of the pulmonary capillary around ventilated alveoli is increased and this may prevent the diffusion of oxygen to the blood furthest away from the alveolar membrane. ichizo, Your email address will not be published. A test of the diffusing capacity of the lungs for carbon monoxide (DLCO, also known as transfer factor for carbon monoxide or TLCO), is one of the most clinically valuable tests of lung function. A reduced KCO cannot indicate the site or scale of the diffusion defect. The unfortunate adoption of certain nomenclature, primarily Dlco/Va (where Va is alveolar volume) can cause confusion on how Dlco assessment is best applied in clinical practice. Several techniques are available to measure Dlco, but the single breath-hold technique is most often employed in PFT laboratories. At least one study has indicated that when the entire exhalation is used to calculate DLCO both healthy patients and those with COPD have a somewhat higher DLCO (although I have reservations about the studys methodology). Another striking example of where Dlco is helpful are cases of difficult-to-control young adult asthmatic women with normal spirometry and lung function who subsequently are diagnosed with PAH secondary to dieting pills or methamphetamines. global version of this site. On a similar note, if a reduction in lung volume is due to an inability to expand the thorax (e.g. WebKco. (2019) Breathe (Sheffield, England). PAH can cause lung restriction but from what I know the effect is fairly homogeneous. If, on the other hand, the patient performs a Muller maneuver (attempts to inhale forcefully against the closed mouthpiece) this will cause negative pressure inside the lung and will increase the capillary blood volume. A deliberately submaximal inspiration in a normal lung will show a very high KCO. This is not necessarily true and as an example DLCO is often elevated in obesity and asthma for reasons that are unclear but may include better perfusion of the lung apices and increased perfusion of the airways. The pathophysiology of pulmonary diffusion impairment in human immunodeficiency virus infection. This understanding is particularly useful in clinical situations in which the expected values do not correlate clinically or with other PFTs such as TLC. Carbon monoxide diffusing capacity (Dlco) probably is the least understood pulmonary function test (PFT) in clinical practice worldwide, even among experienced pulmonologists. startxref Iron deficiency anemia I also have a dull ache across chest area, as if I had done a big run(had for about two months). Although it is nonspecific, a reduced Dlco requires an adequate explanation in every case. <>/ProcSet[/PDF/Text/ImageB]/XObject<>>>/Type/Page>> Carbon monoxide transfer coefficient | Radiology Reference Article For a given gas, the rate of diffusion for this gas, Dl, is dependent upon the thickness of the diffusing membrane (DM, the alveolar-capillary membrane), the rate of uptake of a gas by red blood cells, , and the pulmonary capillary blood volume, Vc. A fit young adult may have a KCO of approximately 1.75 mmol/min/kPa/litre, an elderly adult may be about 1.25. So Yet Another Follow Up - Starting I think 2020 - Bizzar, It's love your pet day today and here is himself . xref Gas transfer (or TLco) test | Asthma + Lung UK DLCO and KCO were evaluated in 2313 patients. Using and Interpreting Carbon Monoxide Diffusing Capacity (Dlco Click Calculate to calculate the predicted values. uuid:8e0822df-1dd2-11b2-0a00-aa0000000000